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Abstract
Polymorphisms in the promoter region are likely to impact KISS1 gene transcription and reproductive traits. In this study, Guanzhong (GZ, n=350) and Boer (BE, n=196) goats were used to detect polymorphism in the promoter of the goat KISS1 gene by DNA sequencing. In the GZ goats, the g.1384G>A mutation was identified in the promoter of the goat KISS1 gene. Guanzhong goats were in Hardy-Weinberg disequilibrium at g.1384G>A locus (P<0.05). The 1384A allele was predicted to eliminate methylation, AHR-arnt heterodimers and AHR-related factors (AHRR) and myoblast determining factors (MYOD) transcription factor-binding sites. Statistical results indicated that the g.1384G>A SNP was associated with litter size in the GZ goats (P<0.05). Luciferase assay analysis suggested that the 1384A allele increased luciferase activity when compared to the 1384G allele. The RT-qPCR assay also demonstrated that the 1384A allele had greater amounts of KISS1 mRNA than the 1384G allele in homozygous individuals. Functional analysis suggested that this g.1384G>A SNP may be an important genetic regulator of KISS1 gene expression with effects on downstream processes that are modulated by KISS1 gene because of the changes of methylation and transcription factor-binding sites. Therefore, the current study provides evidence in goats for genetic markers that might be used in breeding programs.
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... AA with undigested one fragment at 377 bp, TT with two digested fragments at 256 and 121 bp, and AT with three fragments at 377, 256 and 121 bp. Similar to present investigation, 3 different digestion patterns were observed by An et al. (2015) in 3 Chinese goat breeds. Gupta et al. (2015) also observed 3 digestion patterns in Black Bengal goat. ...
... Earlier studies (Chu et al. 2012, An et al. 2013) indicated that KISS1 gene may have some association with prolificacy. An et al. (2015) studied the genetic polymorphism of KISS1 gene in 3 Chinese goat breeds and recorded the association of T-A substitution with the litter size. The frequency of T allele observed in present study was 0.52, which was consistent with earlier report of An et al. (2015) in different Chinese goat populations having frequency of T allele in the range of 0.55-0.60. ...
... An et al. (2015) studied the genetic polymorphism of KISS1 gene in 3 Chinese goat breeds and recorded the association of T-A substitution with the litter size. The frequency of T allele observed in present study was 0.52, which was consistent with earlier report of An et al. (2015) in different Chinese goat populations having frequency of T allele in the range of 0.55-0.60. ...
Migratory goat farming, practiced by nomadic communities is common in Himalayan regions. Gaddi also known as ‘White Himalayan goat’ is the predominant goat breed constituting 60–65% of total goats in the state. The Kisspeptin gene (KISS1) that encodes kisspeptin protein is considered to be a candidate gene affecting multiple birth in goats. The present study was carried out to identify polymorphism at kisspeptin (KISS1 gene) and its association with litter size in migratory Gaddi goat. Polymorphism of KISS1 gene was investigated in Gaddi goats (89) using PCR-RFLP and DNA sequencing approach. PCR-RFLP analysis at KISS1 locus revealed 3 different genotypes, viz. AA with undigested one fragment at 377 bp, TT with two digested fragments at 256 and 121 bp, and AT with three fragments at 377, 256 and 121 bp. The frequencies of AA, AT and TT genotypes were 0.17, 0.52 and 0.31, respectively while the frequency of A and T alleles was 0.43 and 0.57. AT genotype was predominant genotype while AA genotype was having least frequency among the goats screened. The observed allele number (No) and effective allele number (Ne) were 2 and 1.96, respectively. Observed heterozygosity (Hobs), expected heterozygosity (Hexp) and PIC values estimated were 0.52, 0.49 and 0.37, respectively. Hobs and PIC values indicated that sufficient genetic variation exist at the locus. Sequencing of representative sample of different genotypes confirmed presence of SNP (T125A) as detected by PCR-RFLP. The mean litter size for animals belonging to AA, AT and TT genotypes were 1.12±0.08, 1.34±0.11 and 1.73±0.15 kids, respectively. Significant association of genotypes was observed with litter size in Gaddi goat. The study detected association between allele T in KISS1 gene and litter size. Study on additional data based on more number of animals in diversified flocks should be carried out for validation of the preliminary findings.
... Consistent with this, studies have demonstrated that the KISS1 gene substantially contributes to multiparity in goats [84,87]. Moreover, KISS1 gene polymorphisms have been linked to various reproductive traits, including litter size, with several studies confirming the gene's significance in reproductive efficiency [88][89][90][91][92][93]. It has been further documented that the GG genotype at the g.893C>G locus of the KISS1 gene is associated with an increased litter size across three parities, compared to the CC and GC genotypes, in both Iraqi and Cypriot goat populations [89]. ...
... It has been further documented that the GG genotype at the g.893C>G locus of the KISS1 gene is associated with an increased litter size across three parities, compared to the CC and GC genotypes, in both Iraqi and Cypriot goat populations [89]. Similarly, individuals with the AA genotype had greater litter size than those with GG at the g.1384G>A locus in Guanzhong goats [90]. The G-protein-coupled receptor (GPR54) serves as the specific receptor for a group of neuropeptides known as kisspeptins, which are derived from the KISS1 gene. ...
This review examines genetic markers associated with litter size in goats, a key reproductive trait impacting productivity in small ruminant farming. Goats play a vital socioeconomic role in both low- and high-income regions; however, their productivity remains limited due to low reproductive efficiency. Litter size, influenced by multiple genes and environmental factors, directly affects farm profitability and sustainability by increasing the output per breeding cycle. Recent advancements in genetic research have identified key genes and pathways associated with reproductive traits, including gonadotropin-releasing hormone (GnRH), inhibin (INHAA), Kit ligand (KITLG), protein phosphatase 3 catalytic subunit alpha (PPP3CA), prolactin receptor (PRLR), POU domain class 1 transcription factor 1 (POU1F1), anti-Müllerian hormone (AMH), bone morphogenetic proteins (BMP), growth differentiation factor 9 (GDF9), and KISS1 and suppressor of mothers against decapentaplegic (SMAD) family genes, among others. These genes regulate crucial physiological processes such as folliculogenesis, hormone synthesis, and ovulation. Genome-wide association studies (GWASs) and transcriptomic analyses have pinpointed specific genes linked to increased litter size, highlighting their potential in selective breeding programs. By incorporating genomic data, breeding strategies can achieve higher selection accuracy, accelerate genetic gains, and improve reproductive efficiency. This review emphasizes the importance of genetic markers in optimizing litter size and promoting sustainable productivity in goat farming.
... Nevertheless, it is unknown whether rs5780218 is associated with some alterations in the protein function and the absence of a functional insight supporting a regulatory role of this SNP in the KISS1 transcription is an important limitation of this study. It is worth mentioning that the impact of polymorphisms in the promoter region on KISS1 transcription has only been suggested in animal models to date [17]. Functional analysis perfomed in goat cells by using luciferase report assays proposed that a promoter SNP (g.1384G>A) may be an important genetic regulator of KISS1 expression because of the changes of transcription factor binding sites and methylation [17]. ...
... It is worth mentioning that the impact of polymorphisms in the promoter region on KISS1 transcription has only been suggested in animal models to date [17]. Functional analysis perfomed in goat cells by using luciferase report assays proposed that a promoter SNP (g.1384G>A) may be an important genetic regulator of KISS1 expression because of the changes of transcription factor binding sites and methylation [17]. ...
Objectives: This study analyzed the KISS1 c.-145delA (rs5780218) promoter polymorphism in a cohort of patients with growth hormone secreting pituitary adenoma (somatotropinoma) and controls, to investigate its role in the incidence of acromegaly and to assess patient/tumor characteristics. Material and methods rs5780218 allelic and genotypic distributions were compared between 49 somatotropinoma patients and 167 healthy controls. rs5780218 was also assessed in relation to patient characteristics and tumor aggressiveness, as characterized by tumor invasion and resistance to conventional therapy. The relationship between KISS1 mRNA expression and the rs5780218 genotype was also assessed in available pituitary tumor samples. Results: The homozygous -/- variant genotype was associated with high rates of somatotropinoma (P < 0.01), but not with tumor invasiveness, patient characteristics or hormonal remission. KISS1 mRNA expression was much lower in somatotropinomas carrying the deleted allele than in homozygous wild type AA. Conclusions: In this pilot study, the rs5780218 promoter polymorphism was evaluated in pituitary adenoma, and showed a possible association with the incidence of somatotropinoma but not with tumor progression.
... For example, the goat INHA 651A/G polymorphism significantly affected the litter size in Boer goats (Wu et al., 2009). The polymorphism in the promoter region of the KISS1 gene has a notable correlation with the litter size (An et al., 2015a). Additionally, FTH1, growth hormone (GH), and serum amyloid A (SAA) genes were significantly associated with high litter size in Jining Grey goats (Feng et al., 2015). ...
... Previous studies detected that many genetic mutations within candidate genes could affect goat litter size traits. The genetic polymorphism of KISS1 gene was explored and showed that four SNPs may affect litter size in goats (An et al., 2015a). Polymorphisms of GNRH1 and GDF9 genes were identified, and their association with litter size in goats was analyzed (An et al., 2013a). ...
The LIM homeobox transcription factor 4 (LHX4) gene plays a critical role in
regulating the development of the pituitary and the secretion of growth hormone (GH) and prolactin
(PRL) associated with reproduction. Thus this gene may affect litter size. Herein,
the aim of this study is to detect the novel insertion/deletion (indel)
within the LHX4 gene as well as to test its association with litter
size in 1149 Shaanbei white cashmere goats. Herein, a novel 12 bp indel
(NC_030823.1:g.60001011_60001022delGGGGAGGAGGGG) was firstly found,
which was located in the first intron. Meanwhile, three genotypes were detected
in Shaanbei white cashmere goats, and the allelic frequencies of I and
D were 0.593 and 0.407, respectively. Interestingly, the genotype
distributions between mothers of single-lamb (n = 895) and multi-lamb (n = 254) groups within Shaanbei white cashmere goats were significantly
different, implying that the 12 bp indel might affect the litter size.
Furthermore, the association analysis was carried out to find out that the
12 bp indel was significantly associated with litter size in the analyzed
goat population (P < 0.05). The litter sizes of genotype DD and ID
individuals were superior to those of genotype II (P < 0.05). These
findings suggest that this locus could be considered as a genetic marker
for goat breeding, enriching the research category of functional genome of
goats.
... 9 Additionally, in Guangzhong, Saneen, and Xinong goats, a discernible link was found to exist between the KISS1 gene polymorphism and the litter size, 11 a further SNP in the KISS1 gene was discovered in the Guanzhong breed of goat that was associated with litter size. [40][41][42] Research conducted on Egyptian goat breeds (Zaraibi, Baladi, and Barki) indicated that two SNPs in the KISS1 promoter region were substantially linked with litter size. These SNPs were T2124A and C2270T. ...
Background : Litter size (LS) is a significant, challenging, and economical aspect of the goat industry in Indonesia. It is influenced by several different factors and genes; consequently, identifying potential genes and loci associated with litter size has become a genetic problem. Several genetic indicators have been found to be associated with litter size in goats. This has prompted the need to discuss candidate genes associated with litter size in goats in Indonesia.
Methods : A systematic review was conducted using critical databases including ResearchGate, Google Scholar, PubMed, Google search engine and Science direct. There were any exclusion criteria, they were as follows: articles published in languages other than English, Conference papers, short communication papers and papers not related to animals. After reviewing the abstracts of 42 publications, the remaining 17 investigations were chosen for full paper evaluation. A further eight studies were removed after a comprehensive evaluation of the publications because they did not match our inclusion criteria.
Results : These markers include growth differentiation factor 9 ( GDF9 ), bone morphogenetic protein 15 ( BMP15 ), bone morphogenetic protein receptor type IB ( BMPR1B ), and kisspeptin ( KISS1 ). Single nucleotide polymorphisms in these genes contribute to the development of novel genetic markers that helps in the selection of goats with the most favorable genotypes for litter size. This type of genetic selection is more successful than the traditional way of selecting animals for reproductive traits, particularly litter size.
Conclusions : As a result, this study summarizes the genetic impacts of polymorphisms in candidate genes associated with litter size features in Indonesian goats.
... 9 Additionally, in Guangzhong, Saneen, and Xinong goats, a discernible link was found to exist between the KISS1 gene polymorphism and the litter size, 11 a further SNP in the KISS1 gene was discovered in the Guanzhong breed of goat that was associated with litter size. [30][31][32] Research conducted on Egyptian goat breeds (Zaraibi, Baladi, and Barki) indicated that two SNPs in the KISS1 promoter region were substantially linked with litter size. These SNPs were T2124A and C2270T. ...
Background : Litter size (LS) is a significant, challenging, and economical aspect of the goat industry in Indonesia. It is influenced by several different factors and genes; consequently, identifying potential genes and loci associated with litter size has become a genetic problem. Several genetic indicators have been found to be associated with litter size in goats. This has prompted the need to discuss candidate genes associated with litter size in goats in Indonesia.
Methods : A systematic review was conducted using critical databases including ResearchGate, Google Scholar, PubMed, Google search engine and Science direct. There were any exclusion criteria, they were as follows: articles published in languages other than English, Conference papers, short communication papers and papers not related to animals. After reviewing the abstracts of 42 publications, the remaining 17 investigations were chosen for full paper evaluation. A further eight studies were removed after a comprehensive evaluation of the publications because they did not match our inclusion criteria.
Results : These markers include growth differentiation factor 9 ( GDF9 ), bone morphogenetic protein 15 ( BMP15 ), bone morphogenetic protein receptor type IB ( BMPR1B ), and kisspeptin ( KISS1 ). Single nucleotide polymorphisms in these genes contribute to the development of novel genetic markers that helps in the selection of goats with the most favorable genotypes for litter size. This type of genetic selection is more successful than the traditional way of selecting animals for reproductive traits, particularly litter size.
Conclusions : As a result, this study summarizes the genetic impacts of polymorphisms in candidate genes associated with litter size features in Indonesian goats.
... Growth is a complexly detailed biological process that consist of the regulated coordination of a wide diversity of neuro-endocrine pathways, including a coordination of several hormones like growth, thyroxine, insulin, and prolactin hormones, secreted by the endocrine glands and controlled by the action of their corresponding genes [9][10][11][12][13]. It is reported that animals with high levels of these hormones exhibit enhanced growth performance [14][15][16]. ...
Phylogenetic Relationship between Nigerian Goat Breeds and Ecotypes Using Growth Hormone (GH) gene was studied using fifty goats. DNA extraction and amplification using PCR-RFLP were carried out at Molecular Agriculture (IITA), Ibadan, Nigeria. Using standard protocols, the phylogenic tree was established. Tracing the line of evolutionary descent of West Africa Dwarf (WAD) goat and Red Sokoto (RS) goat from a common ancestor, the phylogenic tree showed two major divergences indicating that there are high genetic diversity and similarity of Nigerian goat sub populations. Greater genetic bind between was observed between the WAD from Onitsha axis and RS goats from Anambra, Awka and Onitsha areas. The first divergence was between WAD goats from Anambra area and those from Onitsha, and RS goat breed. In the second divergence, WAD goats from Awka axis differed outrightly from other WAD goat ecotypes and RS breed, indicating that there is an indigenous breed or line at Awka axis which are different from the WAD goats. The study revealed more similarity among RS goats than WAD goat breed. Obviously , the WAD goats are not true breed, rather, conglomeration of all the midgets and bantam found in the tropics.
... It was previously reported [20] that six KiSS1 gene polymorphisms were found in five goat breeds with different prolificacy. Moreover, recently, 11 SNPs were detected in three different goat breeds [3,[28][29][30][31]. ...
Aim:
The study investigated the genetic polymorphism of the kisspeptin (KiSS1) gene and its relationship with litter size in Cyprus and Iraqi black goats.
Materials and methods:
Blood samples (n=124) were collected from the two goat breeds reared at the Agricultural Research-Ruminant Research Station Breeding Station, Baghdad, Iraq. Genomic DNA was isolated using a DNA extraction kit. Polymerase chain reaction (PCR) was used to amplify the KiSS1 gene. All PCR products were sequenced and samples were used for further analysis using NCBI-Blast online on the exon 1 (595 bp) region of the KiSS1 gene.
Results:
The results of this study revealed a significantly (P<0.05) larger litter size of the Cyprus goat breed than in the Iraqi black goats in the first and second parity. Three (893G/C, 973C/A, and 979T/G) substitutions relative to the KiSS1 gene reference sequence (GenBank ID: J × 047312.1, KC989928.1) were identified. Only the mutation g893G>C was identified as a single nucleotide polymorphism (SNP) associated with litter size. Furthermore, the average alleles in KiSS1 gene of both types of goats 0.567 and 0.3715 GG, were recorded. The genotyping at locus g893C>G was demonstrating domination of fecundity quality litter size, Both genotypes SNP of GC were classified at this marked region of KiSS1 gene.
Conclusion:
The study concluded that the role of the KiSS1 gene in fecundity, revealing the status of this gene as an indicator in the assisted of caprine breeding selection.
... This means that the IGF-I stimulates the anterior pituitary for secretion of LH which regulates reproductive activity in mammals (9). It has also been documented that mutation in the promoter region of the genes related to litter size may affect ovulation rate in goats, resulting in a corresponding change in prolificacy in small ruminants (3,16). ...
Pregnancy involves some structural and physiological adjustments to achieve an optimal outcome for the fetus and its mother. The magnitude of these changes is influenced by number of fetuses in utero. This research was designed to compare serum biochemical and ovarian morphometric changes associated with singleton and twin pregnancies in Maradi goats. Using Richardson formula, 2.1 × [CRL (cm) + 17], twelve (12) ovarian and blood samples (7 single and 5 twin) from mid gestation (≈70-100 dGA) pregnant goats were purposively selected. Ovarian weights, ovarian diameters, serum biochemistry and levels of ovarian sex hormones were determined and analyzed using standard procedures. Twin pregnant goats had higher (p < 0.05) left ovarian weights, average ovarian weight, left ovarian diameters, average ovarian diameter, serum calcium and inorganic phosphorus levels compared with singleton pregnant goats. There was no significant variation (p > 0.05) in the mean crown-rump length, mean gestational age, mean fetal weight, right ovarian weights, right ovarian diameters, serum concentrations of sodium, potassium, chloride, urea, creatinine, AST, ALT, total protein, estrogen and progesterone between sinlgeton and twin pregnant Red Maradi goats. Ovarian sections from the twin bearing mid gestation goats had more growing follicles and fewer primordial follicles compared with the singleton bearing goats. Findings from this study indicate that twin pregnancy, which could be genetically programmed, has the tendency to affect ovarian follicles development, ovarian morphometrics and calcium metabolism in mid gestation in Red Maradi goats.
... The mutation found might not be the causal mutation by itself, but might be in linkage disequilibrium with a causal mutation which could affect either KiSS1 gene or other genes near to the KiSS1 locus (Hou et al., 2011). An et al. (2015) identified the g.1384G > A SNP in the KiSS1 gene promoter of goat which may be an essential genetic regulator of KiSS1 gene expression with effects on downstream processes that are modulated by KiSS1 gene because of the changes of methylation and transcription factor-binding sites. ...
... Growth is an intricate biological process that comprises the regulated coordination of a wide diversity of neuro-endocrine pathways, including a coordinated action of several hormones (like growth, thyroxine, insulin, and prolactin hormones) secreted by the key endocrine glands and controlled by the action of their corresponding genes (Ge et al. 2003;Rasouli et al. 2016;An et al. 2015;Othman et al. 2014;Silveira et al. 2008;Zhang et al. 2013). It is well established that animals with high levels of these hormones exhibit enhanced growth performance (Jia et al. 2014;Sodhi et al. 2007;Sharma et al. 2013;Amie Marini et al. 2010;Ayuk and Sheppard 2006). ...
Abstract Background In Egypt, like other developing countries, goats are prime resources of meat. So, selection of goats for superior growth rate is advantageous. Growth hormone (GH) is the main regulator of animal growth, and encoded by GH gene that exhibits active gene variants improving growth. The objective of this study was to identify GH gene variants in three goat breeds (Barki, Damascus, and Zaraibi), via polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) and gene sequencing analyses. Results Three loci on GH gene named GH1, GH2, and GH6 polymorphisms were analyzed. GH1-HaeIII/RFLP showed only two genotypes (AB and BB) in all breeds, with absent AA genotype. Both Barki and Zaraibi exhibited the highest GC genotype frequency (0.95). GH2-HaeIII/RFLP produced only two homozygous genotypes AA in Damascus and BB in both Barki and Zaraibi, with the absence of AB genotype in the three breeds. However, digestion of GH6 by HaeIII was monomorphic; it exhibited different single-nucleotide polymorphisms (SNPs), detected by DNA sequencing, among the studied goat breeds. Conclusions The revealed SNPs could be employed as useful markers, helping goat breeders in selection of goats for high growth performance. Further analyses with larger sample size are needed for investigating the relationship between the different genotypes and growth traits.
... The mutation found might not be the causal mutation by itself, but might be in linkage disequilibrium with a causal mutation which could affect either KiSS1 gene or other genes near to the KiSS1 locus (Hou et al., 2011). An et al. (2015) identified the g.1384G > A SNP in the KiSS1 gene promoter of goat which may be an essential genetic regulator of KiSS1 gene expression with effects on downstream processes that are modulated by KiSS1 gene because of the changes of methylation and transcription factor-binding sites. ...
Understanding the genetic information of related genes is helpful for the selection and breeding course through marker assisted selection. The aim of the current study was to detect polymorphisms of the KiSS1 gene in 137 animals, including Baladi, Zaraibi and Damascus goat breeds by PCR-RFLP, and DNA sequencing and to investigate the association between these variants and reproductive traits. Comparison of the nucleotide sequence indicated the substitution of T with A at position 121 (T121A) in the intron 1 of the KiSS1 gene in all goat breeds. This substitution distorts the restriction site of the XmnI restriction enzyme and consequently two genotypes were detected (TA and TT). The T121A SNP is associated significantly with litter size in Damascus and Zaribi breeds (p= 0.025 and 0.001, respectively). The animals with the TT genotype in Damascus and Zaribi breeds had a significantly higher β-estradiol level than that recorded in TA genotype at estrus phase (p=0.013 and 0.028, respectively) and late-luteal phase (p=0.067 and 0.041, respectively) of the estrus cycle. Furthermore, animals with the TT genotype in Damascus and Zaribi breeds had significant higher progesterone level at mid-luteal (p=0.037 and 0.045, respectively) phase. Meanwhile, there were no significant differences in progesterone level in late-luteal phase between both genotypes in Zaribi breed (p=0.267). The current trial indicated that the prolific TT genotype in both Damascus and Zaribi breeds had superior β-estradiol level at estrus phase and an eminent progesterone level at both early and mid-luteal phases of the estrous cycle.
... The mutation in the promoter region of the genes related to litter size may affect on ovulation rate in goats, resulting in a corresponding change in prolificacy in small ruminants (He et al., 2012;An et al., 2015). Also, some researchers has been observed similar significant assosiation between microsatellite genotypes in 5´ flanking region of the IGF-I gene and prolificacy in goat (Wang et al., 2011) and sheep breeds (He et al., 2012). ...
Growth rate and twinning rate are economic traits that can be used in goat breeding objectives. The aim of this study was to investigate polymorphisms in the insulin-like growth factor 1(IGF-I) and insulin-like growth factor binding protein (IGFBP-3) genes and their relationship with growth traits and twinning in Markhoz goats. Two set of specific primers was used to amplify a 249bp fragment of IGF-I gene and a 316bp fragment of IGFBP-3 gene. PCR-SSCP analysis revealed three banding patterns for each gene that confirmed presence of a mutation in position 1617 of the IGF-I gene and a mutation in position 58 of IGFBP-3 gene. The genotype frequencies of IGF-I gene were 0.81 (GG), 0.16 (GA) and 0.03 (AA). Also, the genotype frequencies of IGFBP-3 gene were 0.79 (TT), 0.17 (TC) and 0.04 (CC). The Odds Ratio estimated for twinning rate was 1.11 for second on first parity, 0.19 for third on first parity and 5.71 for second on third parity . The Chi-square statistics were 6.46 for IGF-I gene and 3.32 for IGFBP-3 gene. The results also indicated that different genotypes of these genes had no significant effect on birth weight, weight at 6 months, at 9 months and at 12 months but the interaction between different genotypes of IGF-I and IGFBP-3 genes were significant for weaning weight and average daily gain from birth to weaning. These results suggest that twinning rate in Markhoz breed is statistically affected by these genes and can be considered in breeding programs.
... This clearly indicates the influence of IGF1 genotypes on prolificacy in goats, probably due to the effect of SNPs in the transcription of the IGF1 gene. The mutation in the promoter region of the genes related to litter size may affect the rate of ovulation in goats, resulting in a corresponding change in prolificacy in small ruminants ( An et al., 2015). Similar significant associations between the 5 flanking region of IGF1 gene and litter size were reported for microsatellite genotypes (121/121 bp, 121/125 bp and 125/125 bp) by Wang et al. (2011) in Chinese goat breeds. ...
The Insulin-Like Growth Factor 1 has an important role in reproduction, foetal development and growth. It regulates the secretion of gonadotrophin releasing hormone, stimulates ovarian function and steroidogenesis. The present study was conducted to characterise the 5′ flanking region of goat IGF1 gene, ascertain ovarian expression of the IGF1gene, detect SNPs and assess the association with prolificacy in the two indigenous goat breeds of South India viz., low prolific Attappady Black and high prolific Malabari. The 5′ flanking region of IGF1 gene was PCR amplified, cloned and sequenced from both breeds. Genotyping was performed in 277 goats from the two genetic groups using the PCR-Single Strand Conformational Polymorphism (SSCP) and the expression of the IGF1 gene in the ovary was analysed by quantitative real time PCR. The 5′ flanking region of the IGF1 gene was 601 bp long and located at 450 bp upstream of the start codon. Sequence exhibited 97% to 99% similarity with that of the sheep, cattle and sika deer IGF1 genes. Three genotypes, PP, PQ and QR were observed at this locus with the frequency of 0.62, 0.30 and 0.08, respectively. Sequencing of the representative PCR products from each genotype revealed two SNPs, g.224A>G and g.227C>T. The population was found to be in Hardy-Weinberg disequilibrium at both loci. Statistical results indicated that these loci were associated with litter size (P ≤ 0.05). However, no significant difference was found in the expression of the IGF1 gene in the ovaries of the two goat breeds. These results suggest the significant influence of the IGF1 gene on prolificacy in goats and identified SNPs would benefit the selection of prolific animals in future breeding programs.
... Their data showed that these functional binding sites in the intron 1 may influence E2F activation, and enhanced activation of E2F could at least in part increase the expression of NCOA3 gene [35]. Previous studies reported that gene polymorphisms may regulate gene expression by changing the binding sites of transcription factors, and may further be associated with specific phenotypes [39,40]. We suppose that intron 1 SNPs of NCOA3 may have potential effect on gene transcription. ...
Nuclear receptor coactivator 2 (NCOA2) gene plays an important role in adipogenesis and lipid metabolism. NCOA2 gene null mice exhibited less fat accumulation and lower serum lipid levels, and were protected against obesity. Few studies are known to have analyzed the association of NCOA2 gene single nucleotide polymorphisms with obesity and serum lipid profile. Our study aimed to evaluate the association of NCOA2 gene polymorphisms with the risk of obesity and dyslipidemia in the Chinese Han population.
Two NCOA2 gene polymorphisms (rs41391448 and rs10504473) were selected and genotyped in a Chinese Han cohort with 529 participants. The effect of different genotypes on BMI and serum lipid levels (TG, TC, LDL-C and HDL-C) was performed by the analysis of covariance. Association of NCOA2 polymorphisms with obesity and dyslipidemia was assessed by odds ratios (OR) and 95% confidence intervals (CI) under the unconditional logistic regression analysis.
Significant association was observed between rs10504473 polymorphism and obesity under the recessive model (OR = 1.88, 95% CI 1.02-3.45, P = 0.047; adjusted OR = 1.87, 95% CI 1.02-3.44, P = 0.048). However, no association remained significant after Bonferroni correction.
Our study suggests a possible association between NCOA2 rs10504473 polymorphism and obesity, and this SNP may influence the susceptibility of obesity in the Chinese Han population.
KiSS-1 gene encodes a protein product kisspeptin which are intense inducers of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion in various mammalian species through its receptor GPR54 (G protein-coupled receptor-54). A total of 100 goat compromising of Red Sokoto (n = 72) and Sahel (n = 28) breeds were used to detect single nucleotide polymorphisms (SNPs) in the intronic region of the KiSS-1 gene by sequencing and investigate their relationship with other goat breeds. Nucleotide sequence analysis revealed five novel SNPs (g.1745G>A present in Red Sokoto, g.1776G>A, g.1827A>G, g.1857T>C and g.2208T>C present in Red Sokoto and Sahel breeds). To obtain a correct phylogenetic relationship between goat breeds, nucleotide sequences were compared to other sequences in NCBI database using a BLASTn algorithm and retrieved for further analysis. Neighbour-joining phylogenetic relationship tree constructed revealed two distinct clusters with ancestral lineage of 100% identity. Nigerian goat breeds (Red Sokoto and Sahel) clustered into a clade with Indian goat breeds (Ganjam and Osmanabadi) while the second cluster involved eight other goat breeds. Genetic distance estimate revealed high genetic similarity between Red Sokoto and Sahel breeds as observed in their genetic distance value of 0.003. The nucleotide sequences of the two Nigerian goat breeds (Red Sokoto and Sahel) for KiSS-1 gene were submitted to GenBank database and have accession numbers: MN122316 and MN122317, respectively. The analysis of polymorphism in KiSS-1 gene indicates that genetic variation exists in the goat breeds studied. Therefore, attempts can be made to investigate the association of these polymorphism with reproductive traits in Nigerian goat breeds.
Membrane-associated RING CH-type finger 1(MARCH1) gene belongs to a family member of RING-v type E3 ubiquitin ligases, which consists of 11 known members, some of which targets important aspects of immune response. MARCH1 gene has a regulatory role in immunity and placental health; hence it affects foetal growth and survivability. To understand the role of MARCH1 gene in caprine reproduction, differential gene expression profile was studied in reproductive tissues of goats. Relative abundance of MARCH1 mRNA was significantly (≤0.01) higher in placenta than ovaries, uterus and fallopian tubes. Further, the differential placental gene expression profile was studied in two groups of goats with normal kidding and kid mortality at birth. MARCH1 gene was significantly upregulated in the placenta of goats with early kid mortality than normal kidding. An indel mutation (a 7 bp insertion) located in the promoter region of MARCH1 gene was screened in 282 goats belonging to Malabari and Attappady Black breeds by agarose gel electrophoresis and revealed three genotypes (DD, ID and II). A novel High resolution melt curve analysis protocol was designed for the rapid screening of this indel. Genotype II had higher litter size and average birth weight of kids than ID and DD genotypes. These results suggest the influence of the detected indel in placental health and foetal growth, together the role of MARCH1 in reproduction as well as the potential use of indel in MARCH1 as a molecular marker in future goat breeding programmes.
Background: India is fortunate to have a vast livestock resource with the availability of 28 well defined goat breeds. Kerala is the home for two breeds of goats namely Malabari and Attapady Black. Due to high prolificacy and income through lower input goat rearing had attracted numerous farmers. Selection with the aid of molecular markers associated with production traits plays an essential role in goat breeding programmes. The EGR2 gene is a part of multigene family which encodes Cys2His2 type zinc-finger proteins which is responsible for DNA binding. This gene has a major role in cellular prolification, reproduction, proper growth and development ovarian follicles. Thus present study was conducted with an objective to detect single nucleotide variations of Early Growth Response 2 gene in native goat breeds of Kerala. Methods: This research was conducted in 153 Malabari goats and 129 Attappady Black goats from six centers viz., University Goat and Sheep farm Mannuthy and 5 field centers of ICAR- All India Coordinated Research Project on Goat Improvement. Genomic DNA was isolated and PCR was performed to amplify Exon 1, Exon 2 and 5 fragments of Exon 3 regions of Early Growth Response 2 gene. Single stranded conformation polymorphism (SSCP) technique was performed to detect Single Nucleotide Polymorphism (SNPs). Result: The SSCP revealed similar banding patterns and sequencing did not indicate any nucleotide variations in all the exons screened suggesting that EGR2 gene is highly conserved in native goat breeds of Kerala. This is the first study conducted to characterize EGR2 gene in goats making the current study a novel one.
The Kiss1 gene plays an indispensable role in modulating the onset of puberty and fertility in mammals. Although an increasing number of genetic and environmental factors that influence reproduction through Kiss1 have been identified, the function of microRNAs, a class of posttranscriptional regulators, in regulating Kiss1 expression remains poorly understood. This study aimed at investigating the mechanism by which Kiss1 expression is regulated by microRNAs. A simplified miRNome screen by a dual-fluorescence reporter system based on Kiss1 was performed to identify microRNAs that affect the expression of Kiss1. The expression patterns of the identified microRNAs during the period of murine sexual development were investigated, and only miR-199-3p was studied further. Aided by bioinformatics algorithms, miR-199-3p was demonstrated to be a repressor of Kiss1 expression, as it blocked the expression of Kiss1 through the p38 MAPK pathway by simultaneously inhibiting several targets in both GT1-7 cells and primary hypothalamic neurons. Both the inhibition of the p38 MAPK pathway by the intracerebroventricular administration of chemical agents in rats and the ectopic expression of miR-199-3p by lentivirus injection in the hypothalamus in mice delayed puberty onset and gonad development. Our results presented a novel regulatory mechanism of puberty onset which the sustained downregulation of miR-199-3p might gradually release the inhibition of the p38 MAPK/Fos/CREB/Kiss1 pathway during puberty development.
CKLF-like MARVEL transmembrane domain-containing 2 (CMTM2) plays an important role in animal reproduction, and abnormal CMTM2 expression leads to spermatogenesis disorders. This study was conducted to assess the role of CMTM2 in goat reproduction by investigating an insertion/deletion (indel) variation and its effect on litter size, and to reveal its functional mechanism. A 14-base pair (bp) indel was found at position -861 to -848 nt of the CMTM2 promoter in 1131 female Shaanbei white cashmere goats. Association analyses revealed that the 14-bp indel in dams was significantly correlated with the size of the first litter (P = 0.013), with the 14-bp deletion significantly decreasing litter size. Moreover, litter size at first kidding was significantly correlated with genotype frequencies (P = 0.019). Expression of the goat CMTM2 gene was detected in testes and ovaries. In male, CMTM2 was increased after the initiation of meiosis in the developing testis. In female, CMTM2 expression was higher in ovary from multiple prolific goats at first kidding compared to non-prolific goats. Moreover, both in testis after initiation of meiosis and in ovary, the homozygous 14-bp inserted genotype II was associated with increased CMTM2 expression compared to the heterozygous genotype ID (P < 0.05). To further explore whether the 14-bp indel was located in the core promoter activity region of the CMTM2 promoter, the five recombinant plasmids pGL3-pro1 (-1756 to +83), pGL3-pro2 (-1200 to +83), pGL3-pro3 (-763 to +83), pGL3-pro4 (-496 to +83), and pGL3-pro5 (-205 to +83) were co-transfected with pRL-TK into HEK293T and GC-1 cells. A luciferase reporter assay showed that the pGL3-pro2 and pGL3-pro5 vectors produced significantly stronger luminescence than the other vectors. Interestingly, the 14-bp indel locus was included in the pGL3-pro2 plasmid, suggesting that the indel was functional. Subsequently, the two recombinant plasmids pGL3-pro2-inserted-allele and pGL3-pro2-deleted-allele were co-transfected with pRL-TK into HEK293T and GC-1 cells, respectively. The luciferase reporter assay demonstrated that the deleted allele of CMTM2 showed significantly lower luminescence activity than the inserted allele (P < 0.05), which corresponded to a decrease in litter size in the deletion-deletion genotype. Therefore, our results suggest that a 14-bp deletion in the promoter region of CMTM2 is significantly correlated with litter size in goats; this marker seems promising for breeding selection for improving economically important traits in goats.
Sirtuin 4 (SIRT4) belongs to the mitochondrial sirtuin class of NAD+-dependent protein deacylases. This gene plays an important role in the regulation of lipid metabolism, cellular growth, and metabolism in mammals. Here, potential polymorphisms were sought in the bovine SIRT4 gene, and the relationships between the detected polymorphisms and carcass quality in Qinchuan cattle were assessed. Four single nucleotide polymorphisms (SNPs) were identified in the promoter region of the SIRT4 gene from the sequencing results of 452 individual cattle. A total of 8 different haplotypes were identified. Of these, the 3 most frequently observed haplotypes had frequencies of 35.0% (-CTG-), 18.3% (-CTA-), and 12.9% (-CCG-). The frequencies of g.-311C > T, g.-771C > T, and g.-1022G > A conformed to Hardy-Weinberg equilibrium in all the samples (chi-square test, P < 0.05). The association analysis indicated that these 3 polymorphisms were significantly associated with subcutaneous fat depth and intramuscular fat content (at P < 0.01 or P < 0.05). Interestingly, the Hap1/2 (-CAG-CAA-) diplotype was more highly associated with desirable ultrasound than other haplotype combinations.
The Nuclear receptor superfamily 5, group A, member 1 (NR5A1) gene encodes a nuclear receptor that regulates the transcription of genes involved in steroidogenesis, follicular development and female fertility. Little, however, is known about the relationship of this gene with reproductive performance in sheep. In this study, the transcription initiation site of Hu sheep NR5A1 gene was located 193 nucleotides (i.e., at -193 nt) before the translational start site (ATG). The core promoter region of the NR5A1 gene ranged from -696 nt to -298 nt, and a C>G mutation at -388 nt was detected in this region. Association analysis indicated ewes with the GG genotype had greater litter size at the second and third parity than those with the CC genotype (P < 0.05). The results from the luciferase assay provided evidence that the -388 G allele increased luciferase activity compared with that of the -388 C allele. Furthermore, the -388 C>G mutation lost a CpG site and gained a novel binding site for the transcription factor, SP1, and results from an overexpression experiment and methylation analysis indicated transcription factor SP1 and methylation of the -388 C>G mutation were both involved in alteration of NR5A1 transcription activity. Results of the present study revealed that the -388 C>G mutation lost a CpG site and promoted NR5A1 gene expression, which completely superimposed positive effects on NR5A1 gene transcription activity by transcription factor SP1, resulting in a fecundity increase in Hu sheep.
Objectives:
This study observes therapeutic efficacy of uterine artery embolization combined with MTX infusion which terminates cesarean scar pregnancy (CSP) and induces three factors which probably relate to failure.
Methods:
Twenty-three CSP patients were treated with combined uterine artery MTX infusion and embolization. Among them six patients with severe hemorrhage were immediately treated with interventional operation. Clinical effects were estimated by symptoms, serum β-hCG, ultrasound, and MR.
Results:
Interventional treatments were technologically successful in 22 patients except one. Immediate hemostasis was achieved in all 6 patients with massive colporrhagia. No occurrence of infection and uterine necrosis was observed, but 12 women suffered abdominal pains. Nineteen patients' uteri were preserved, whereas four underwent hysterectomy eventually.
Conclusions:
Transcatheter arterial chemoembolization is effective to treat high-risk CSP in preference to hysterectomy. To achieve more successful outcomes, three factors should be highlighted: adequate MTX dosage, appropriate embolic material, and complete embolization of target arteries that supply blood to embryo in the scar.
Kisspeptins are the peptide products of KISS1 gene, which operate via the G - protein-coupled receptor GPR54. These peptides have emerged as essential upstream regulators of neurons secreting gonadotropin-releasing hormone (GnRH), the major hypothalamic node for the stimulatory control of the hypothalamic-pituitary- gonadal (HPG) axis. The present study detected the polymorphisms of caprine KISS1 gene in three goat breeds and investigated the associations between these genetic markers and litter size.
Three goat breeds (n = 680) were used to detect single nucleotide polymorphisms (SNPs) in the coding regions with their intron-exon boundaries and the proximal flanking regions of KISS1 gene by DNA sequencing and PCR-RFLP. Eleven novel SNPs (g.384G>A, g.1147T>C, g.1417G>A, g.1428_1429delG, g.2124C>T, g.2270C>T, g.2489T>C, g.2510G>A, g.2540C>T, g.3864_3865delCA and g.3885_3886insACCCC) were identified. It was shown that Xinong Saanen and Guanzhong goat breeds were in Hardy-Weinberg disequilibrium at g.384G>A locus (P < 0.05). Both g.2510G>A and g.2540C>T loci were closely linked in Xinong Saanen (SN), Guanzhong (GZ) and Boer (BG) goat breeds (r2 > 0.33). The g.384G>A, g.2489T>C, g.2510G>A and g.2540C>T SNPs were associated with litter size (P<0.05). Individuals with AATTAATT combinative genotype of SN breed (SC) and TTAATT combinative genotype of BG breed (BC) had higher litter size than those with other combinative genotypes in average parity. The results extend the spectrum of genetic variation of the caprine KISS1 gene, which might contribute to goat genetic resources and breeding.
This study explored the genetic polymorphism of KISS1 gene, and indicated that four SNPs may play an important role in litter size. Their genetic mechanism of reproduction in goat breeds should be further investigated. The female goats with SC1 (AATTAATT) and BC7 (TTAATT) had higher litter size than those with other combinative genotypes in average parity and could be used for the development of new breeds of prolific goats. Further research on a large number of animals is required to confirm the link with increased prolificacy in goats.
Kisspeptins (Kiss) are prime players in the control of reproductive function through their regulation of gonadotropin-releasing hormone (GnRH) expression in the brain. The experimental scombroid fish, chub mackerel (Scomber japonicus) expresses two kiss (kiss1 and kiss2) and three gnrh (gnrh1, gnrh2, and gnrh3) forms in the brain. In the present study, we analyzed expression changes of kiss and gnrh mRNAs in the brain and corresponding GnRH peptides in the brain and pituitary during final ovarian maturation (FOM) and ovulation.
Female fish possessing late vitellogenic oocytes were injected with GnRH analogue to induce FOM and ovulation. Fish were observed for daily spawning activities and sampled one week post-injection at germinal vesicle migration (GVM), oocyte hydration, ovulation, and post-ovulatory time periods. Changes in relative mRNA levels of kiss and gnrh forms in the brain were determined using quantitative real-time PCR. Changes in GnRH peptides in the brain and pituitary were analyzed using time-resolved fluoroimmunoassay.
Both kiss1 and kiss2 mRNA levels in the brain were low at late vitellogenic stage and increased significantly during the GVM period. However, kiss1 mRNA levels decreased during oocyte hydration before increasing again at ovulatory and post-ovulatory periods. In contrast, kiss2 mRNA levels decreased at ovulatory and post-ovulatory periods. Levels of gnrh1 mRNA in the brain increased only during post-ovulatory period. However, levels of gnrh2 and gnrh3 mRNAs were elevated during GVM and then, decreased during oocyte hydration before increasing again at ovulatory period. During post-ovulatory period, both gnrh2 and gnrh3 mRNA levels declined. Peptide levels of all three GnRH forms in the brain were elevated during GVM and oocyte hydration; their levels were significantly lower during late vitellogenic, ovulatory, and post-ovulatory periods. In contrast, pituitary GnRH peptide levels did not show any significant fluctuations, with the GnRH1 peptide levels being many-fold higher than the GnRH2 and GnRH3 forms.
The results indicate increased expression of multiple Kiss and GnRH forms in the brain and suggest their possible involvement in the regulation of FOM and ovulation in captive female chub mackerel.
Three pairs of primers were designed to clone the goat KiSS-1 and scan polymorphisms and four pairs to detect polymorphisms in sexual precocious and sexual late-maturing goat breeds. A 4118 bp DNA fragment was obtained, which contains an ORF of 408 bp and encodes 135 amino acids, having a high homology with other mammals. The protein was predicted containing a signal peptide of 17 amino acids. There are two mutations (G3433A [A86T] and C3688A) in exon 3, three mutations (G296C, G454T and T505A) in intron 1 and a 18 bp deletion (-)/insertion (+) (1960-1977) in intron 2 and no mutations in exon 2. The genotype distribution didn't show obvious difference between sexual precocious and sexual late-maturing goat breeds and no consistency within the sexual late-maturing breeds. For the 296 locus, the Jining Grey goats with genotype CC had 0.80 (P < 0.01) or 0.77 (P < 0.01) kids more than those with genotype GG or GC, respectively. No significant difference (P > 0.05) was found in litter size between GG and GC. For the 1960-1977 locus, the Jining Grey goat does with genotype -/- had 0.77 (P < 0.01) or 0.73 (P < 0.01) kids more than those with +/+ or +/-, respectively. No significant difference (P > 0.05) was found in litter size between +/+ and +/- genotypes. For the other four loci, no significant difference (P > 0.05) was found in litter size between different genotypes in Jining Grey goats. The present study preliminarily indicated an association between allele C of the 296 locus and allele (-) of the 1960-1977 locus in KiSS-1 and high litter size in Jining Grey goats.
Kisspeptin, encoded by the KISS1 gene, is a key stimulatory factor of GnRH secretion and puberty onset. Inactivating mutations of its receptor (KISS1R) cause isolated hypogonadotropic hypogonadism (IHH). A unique KISS1R-activating mutation was described in central precocious puberty (CPP).
Our objective was to investigate KISS1 mutations in patients with idiopathic CPP and normosmic IHH.
Eighty-three children with CPP (77 girls) and 61 patients with IHH (40 men) were studied. The control group consisted of 200 individuals with normal pubertal development.
The promoter region and the three exons of KISS1 were amplified and sequenced. Cells expressing KISS1R were stimulated with synthetic human wild-type or mutant kisspeptin-54 (kp54), and inositol phosphate accumulation was measured. In a second set of experiments, kp54 was preincubated in human serum before stimulation of the cells.
Two novel KISS1 missense mutations, p.P74S and p.H90D, were identified in three unrelated children with idiopathic CPP. Both mutations were absent in 400 control alleles. The p.P74S mutation was identified in the heterozygous state in a boy who developed CPP at 1 yr of age. The p.H90D mutation was identified in the homozygous state in two unrelated girls with CPP. In vitro studies revealed that the capacity of the P74S and H90D mutants to stimulate IP production was similar to the wild type. After preincubation of wild-type and mutant kp54 in human serum, the capacity to stimulate signal transduction was significantly greater for P74S compared with the wild type, suggesting that the p.P74S variant is more stable. Only polymorphisms were found in the IHH group.
Two KISS1 mutations were identified in unrelated patients with idiopathic CPP. The p.P74S variant was associated with higher kisspeptin resistance to degradation in comparison with the wild type, suggesting a role for this mutation in the precocious puberty phenotype.
Kisspeptin-GPR54 signaling plays an essential role in normal reproduction in mammals via stimulation of gonadotropin secretion. Here, we cloned the porcine KISS1 cDNA from the hypothalamic tissue and investigated the effect of estrogen on the distribution and numbers of KISS1 mRNA-expressing cells in the porcine hypothalamus. The full length of the cDNA was 857 bp encoding the kisspeptin of 54 amino acids, with the C-terminal active motif designated kisspeptin-10 being identical to that of mouse, rat, cattle, and sheep. In situ hybridization analysis revealed that KISS1-positive cell populations were mainly distributed in the hypothalamic periventricular nucleus (PeN) and arcuate nucleus (ARC). KISS1 expression in the PeN of ovariectomized (OVX) pigs was significantly upregulated by estradiol benzoate (EB) treatment. On the other hand, KISS1-expressing cells were abundantly distributed throughout the ARC in both OVX and OVX with EB animals. The number of KISS1-expressing neurons was significantly lowered by EB treatment only in the most caudal part of the ARC, but other ARC populations were not affected. The present study thus suggests that the PeN kisspeptin neurons could be responsible for the estrogen positive feedback regulation to induce gonadotropin-releasing hormone/luteinizing hormone (GnRH/LH) surge in the pig. In addition, the caudal ARC kisspeptin neurons could be involved in the estrogen negative feedback regulation of GnRH/LH release. This is the first report of identification of porcine KISS1 gene and of estrogen regulation of KISS1 expression in the porcine brain, which may be helpful for better understanding of the role of kisspeptin in reproduction of the pig.
Differences in the type of base methylated (cytosine or adenine) and in the extent of methylation were detected by high-pressure liquid chromatography in the DNAs of five spiroplasmas. Nearest neighbor analysis and digestion by restriction enzyme isoschizomers also revealed differences in methylation sequence specificity. Whereas in Spiroplasma floricola and Spiroplasma sp. strain PPS-1 5-methylcytosine was found on the 5' side of each of the four major bases, the cytosine in Spiroplasma apis DNA was methylated only when its 3' neighboring base was adenine or thymine. In Spiroplasma sp. strain MQ-1 over 95% of the methylated cytosine was in C-G sequences. Essentially all of the C-G sequences in the MQ-1 DNA were methylated. Partially purified extracts of S. apis and Spiroplasma sp. strain MQ-1 were used to study substrate and sequence specificity of the methylase activity. Methylation by the MQ-1 enzyme was exclusively at C-G sequences, resembling in this respect eucaryotic DNA methylases. However, the MQ-1 methylase differed from eucaryotic methylases by showing high activity on nonmethylated DNA duplexes, low activity with hemimethylated DNA duplexes, and no activity on single-stranded DNA.
With an ever-increasing resource of validated single-nucleotide polymorphisms (SNPs), the limiting factors in genome-wide association analysis have become genotyping capacity and the availability of DNA. We provide a proof of concept of the use of pooled DNA as a means of efficiently screening SNPs and prioritizing them for further study. This approach reduces the final number of SNPs that undergo full, sample-by-sample genotyping as well as the quantity of DNA used overall. We have examined 15 SNPs in the cholesteryl ester transfer protein (CETP) gene, a gene previously demonstrated to be associated with serum high-density lipoprotein cholesterol levels. The SNPs were amplified in two pools of DNA derived from groups of individuals with extremely high and extremely low serum high-density lipoprotein cholesterol levels, respectively. P values <0.05 were obtained for 14 SNPs, supporting the described association. Genotyping of the individual samples showed that the average margin of error in frequency estimate was approximately 4% when pools were used. These findings clearly demonstrate the potential of pooling techniques and their associated technologies as an initial screen in the search for genetic associations.
Kisspeptins are products of the KiSS-1 gene, which bind to a G protein-coupled receptor known as GPR54. Mutations or targeted disruptions in the GPR54 gene cause hypogonadotropic hypogonadism in humans and mice, suggesting that kisspeptin signaling may be important for the regulation of gonadotropin secretion. To examine the effects of kisspeptin-54 (metastin) and kisspeptin-10 (the biologically active C-terminal decapeptide) on gonadotropin secretion in the mouse, we administered the kisspeptins directly into the lateral cerebral ventricle of the brain and demonstrated that both peptides stimulate LH secretion. Further characterization of kisspeptin-54 demonstrated that it stimulated both LH and FSH secretion, at doses as low as 1 fmol; moreover, this effect was shown to be blocked by pretreatment with acyline, a potent GnRH antagonist. To learn more about the functional anatomy of kisspeptins, we mapped the distribution of KiSS-1 mRNA in the hypothalamus. We observed that KiSS-1 mRNA is expressed in areas of the hypothalamus implicated in the neuroendocrine regulation of gonadotropin secretion, including the anteroventral periventricular nucleus, the periventricular nucleus, and the arcuate nucleus. We conclude that kisspeptin-GPR54 signaling may be part of the hypothalamic circuitry that governs the hypothalamic secretion of GnRH.
Motivation: Promoter analysis is an essential step on the way to identify regulatory networks. A prerequisite for successful promoter analysis is the prediction of potential transcription factor binding sites (TFBS) with reasonable accuracy. The next steps in promoter analysis can be tackled only with reliable predictions, e.g. finding phylogenetically conserved patterns or identifying higher order combinations of sites in promoters of co-regulated genes.
Results: We present a new version of the program MatInspector that identifies TFBS in nucleotide sequences using a large library of weight matrices. By introducing a matrix family concept, optimized thresholds, and comparative analysis, the enhanced program produces concise results avoiding redundant and false-positive matches. We describe a number of programs based on MatInspector allowing in-depth promoter analysis (DiAlignTF, FrameWorker) and targeted design of regulatory sequences (SequenceShaper).
Availability: MatInspector and the other programs described here can be used online at http://www.genomatix.de/matinspector.html. Access is free after registration within certain limitations (e.g. the number of analysis per month is currently limited to 20 analyses of arbitrary sequences).
Contact:cartharius@genomatix.de
Supplementary information:http://www.genomatix.de/matinspector.html
The KiSS-1 gene encodes a family of peptides called kisspeptins, which are endogenous ligands for the G protein-coupled receptor GPR54. Kisspeptin function appears to be critical for GnRH secretion and the initiation of puberty. To test the hypothesis that steroid hormones regulate KiSS-1 mRNA expression in the ewe, we examined the brains of ovary-intact (luteal phase) and ovariectomized (OVX) ewes, as well as OVX ewes that received estradiol (E) or progesterone (P) replacement. KiSS-1 mRNA-expressing cells were predominantly located in the arcuate nucleus (ARC). Here, expression was increased after OVX but returned to the level of gonad-intact animals with E treatment. Treatment with P partially restored KiSS-1 expression toward gonad-intact levels. Double-label immunohistochemistry revealed that approximately 86% of kisspeptin-immunoreactive cells in the ARC are also P-receptor positive. Finally, we tested the hypothesis that KiSS-1 mRNA is lower during anestrus, due to a non-steroid-dependent seasonal effect. In OVX ewes, expression in the ARC was lower at the time of year corresponding to anestrus. We conclude that KiSS-1 expression in the ARC of the ewe brain is negatively regulated by chronic levels of E and P, suggesting that both steroids may exert negative feedback control on GnRH secretion through altered kisspeptin signaling. Furthermore, a seasonal alteration in KiSS-1 expression in the ARC of OVX ewes strongly suggests that kisspeptin is fundamentally involved in the control of seasonal changes in reproductive function.
The G protein-coupled receptor GPR54 (AXOR12, OT7T175) is central to acquisition of reproductive competency in mammals. Peptide ligands (kisspeptins) for this receptor are encoded by the Kiss1 gene, and administration of exogenous kisspeptins stimulates hypothalamic gonadotropin-releasing hormone (GnRH) release in several species, including humans. To establish that kisspeptins are the authentic agonists of GPR54 in vivo and to determine whether these ligands have additional physiological functions we have generated mice with a targeted disruption of the Kiss1 gene. Kiss1-null mice are viable and healthy with no apparent abnormalities but fail to undergo sexual maturation. Mutant female mice do not progress through the estrous cycle, have thread-like uteri and small ovaries, and do not produce mature Graffian follicles. Mutant males have small testes, and spermatogenesis arrests mainly at the early haploid spermatid stage. Both sexes have low circulating gonadotropin (luteinizing hormone and follicle-stimulating hormone) and sex steroid (β-estradiol or testosterone) hormone levels. Migration of GnRH neurons into the hypothalamus appears normal with appropriate axonal connections to the median eminence and total GnRH content. The hypothalamic–pituitary axis is functional in these mice as shown by robust luteinizing hormone secretion after peripheral administration of kisspeptin. The virtually identical phenotype of Gpr54- and Kiss1-null mice provides direct proof that kisspeptins are the true physiological ligand for the GPR54 receptor in vivo. Kiss1 also does not seem to play a vital role in any other physiological processes other than activation of the hypothalamic–pituitary–gonadal axis, and loss of Kiss1 cannot be overcome by compensatory mechanisms.
• Gpr54
• kisspeptin
• mouse
• puberty
Kisspeptin, the endogenous ligand of the G protein-coupled receptor 54, is a key regulator of the hypothalamo-pituitary-gonadal (HPG) axis. GPR54-null mice exhibit reproductive dysfunction, and exogenous kisspeptin potently stimulates the HPG axis in rodents, primates, and human males. The effects of kisspeptin administration to human females are unknown.
Our objective was to investigate the effects of kisspeptin on LH release during the menstrual cycle in female volunteers.
Bolus sc kisspeptin-54 was administered to female volunteers, and plasma gonadotropins were measured.
The study took place at a hospital clinical research facility.
Subjects were healthy female volunteers with regular menstrual cycles. Intervention: 1) Volunteers received a sc bolus injection of kisspeptin-54 (0, 0.2, 0.4, 0.8, 1.6, 3.2, and 6.4 nmol/kg; n = 3-4 per dose) in the follicular phase; and 2) volunteers (n = 8) received a sc bolus injection of either kisspeptin-54 (0.4 nmol/kg) or saline in random order during each phase of the menstrual cycle.
Plasma gonadotropins were measured.
1) Kisspeptin-54 caused a dose-dependent increase in mean LH over time at doses from 0.2-6.4 nmol/kg. 2) Kisspeptin-54 increased plasma LH compared with saline injection in all phases of the cycle. The effect of kisspeptin was greatest in the preovulatory phase and least in the follicular phase of the cycle [mean increase in LH over baseline (IU/liter) +/- sem for follicular phase was 0.12 +/- 0.17; preovulatory phase, 20.64 +/- 2.91 (P < 0.001 vs. follicular phase); luteal phase, 2.17 +/- 0.79 (P < 0.01 vs. follicular phase)].
Elevation of plasma kisspeptin in human females potently stimulates LH release in the preovulatory phase and provides a novel mechanism for manipulation of the HPG axis in women.
Serotonin (5-HT) is thought to be critical for affect regulation in the brain and many antidepressants are thought to primarily work by altering 5-HT levels. However there has not been a validated means of directly imaging of endogenous 5-HT levels in humans. The main aims of this project are to image the effect of Citalopram on brain endogenous 5-HT levels and to determine the relationship between brain 5-HT and affect regulation.Methods
Thirteen healthy volunteers (mean age 50.9yrs, range 35–63) underwent two Positron Emission Tomography (PET) scans with [11C]-CUMI, a highly selective 5-HT1A agonist radioligand. Subjects received either a slow intravenous infusion of citalopram 10mg or saline starting 45 minutes before each PET scan in a randomized design. All subjects had a functional MRI emotion processing task (block design) known to activate the amygdala on a separate day.ResultsThe citalopram infusion induced 6–11% increases in [11C]-CUMI binding potential in anterior cingulate, insula and cortical brain regions (p < 0.05 corrected for repeated measures).BOLD response to fearful vs neutral faces in the left amygdala inversely correlated with baseline dorsal raphe BP (Pearson r2 =−0.90, p < 0.001) and directly correlated with dorsal raphe BP changes (r2=0.51, p = 0.07).Conclusion
The increase in [11C]CUMI-101 availability would be consistent with a decrease in endogenous 5-HT availability in certain terminal regions. The relationship between brain emotion processing and [11C]-CUMI binding in the raphe indicates the 5-HT levels at presynaptic receptors regulate emotional processing and suggests presynaptic 5-HT as a treatment target for affective disorders.
Adolescent girls with polycystic ovary syndrome (PCOS) manifest neuroendocrine derangements after the onset of puberty, characterized by rapid LH pulse frequency. The early mechanism underlying the pubertal regulation of the GnRH/LH pulsatile release in adolescents with PCOS remains uncertain. To determine the effects of prenatal androgen exposure on the activation of GnRH neurons and generation of LH pulse at puberty, we administrated DHT to pregnant rats and observed serum LH levels and hypothalamic genes expression in female offspring from postnatal 4 to 8 weeks. The 6-week-old prenatally androgenized (PNA) female rats exhibited an increase in LH pulse frequency. The hypothalamic expression of NKB and ObRb mRNAs in PNA rats remarkably increased before puberty and remained high during puberty, whereas elevated Kiss1 mRNA levels were detected only after the onset of puberty. Exogenous Kisspeptin, NK3R agonist and Leptin exerted tonic stimulation of GnRH neurons and increased LH secretion in the 6-week-old PNA rats. Leptin up-regulated Kiss1 mRNA levels in the hypothalamus of pubertal PNA rats; however, pretreatment with a Kisspeptin antagonist failed to suppress the elevated serum LH stimulated by Leptin, indicating that the stimulatory effects of Leptin may be conveyed indirectly to GnRH neurons via other neural components within the GnRH neuronal network, rather than through the Kisspeptin-GPR54 pathway. These findings validate that NKB and Leptin play an essential role in the activation of GnRH neurons and initiation of increased LH pulse frequency in PNA female rats at puberty and Kisspeptin may coordinate their stimulatory effects on LH release.
Higher average daily gain, more lean meat yield and less fat yield of porcine carcass increase selling profits for animal producers. Myostatin (MSTN), previously called GDF8, is a member of transforming growth factor-β (TGF-β) superfamily. It is a negative regulator for both embryonic development and adult homeostasis of skeletal muscle. In this study, the genotypes of the previously described SNPs MSTN g.435G>A and g.447A>G SNPs in 66 Duroc pigs, 33 Landrace pigs, 180 Duroc × Landrace (DL) pigs and 155 Duroc × Yorkshire × Landrace (DYL) pigs were determined by Taqman SNP Genotyping Assays. For Duroc and Landrace pigs, MSTN g.435GG/g.447AA individual had greater backfat thickness (p < 0.05) than g.435AA/g.447GG individual, whereas MSTN g.435AA/g.447GG had greater meat (p < 0.05) and meat percentage (p < 0.05) than g.435GA/g.447AG individual. For DL and DYL pigs, the MSTN g.435GG/g.447AA animals were greater in backfat at ultrasound 10th rib (p < 0.05) and carcass 10th rib (p < 0.01) than g.435AA/g.447GG individual. The MSTN g.435AA/g.447GG individual also had higher values than g.435GG/g.447AA for anterior-end meat (p < 0.05), posterior-end meat (p < 0.01), total meat weight (p < 0.01) and meat percentage (p < 0.01). This study confirmed evidence that MSTN g.435G>A and g.447A>G affected carcass traits in pigs. The effects of the mutated alleles were additive with the maximal effects resulting from two copies of the mutated allele. Selection for MSTN g.435A/g.447G allele is expected to increase muscle of limb and total meat production and decrease backfat thickness.
Kisspeptin (Kiss1) signaling to gonadotropin releasing hormone neurons is widely acknowledged to be a prerequisite for puberty and reproduction. Animals lacking functional genes for either kisspeptin or its receptor exhibit low gonadotropin secretion and infertility. Paradoxically, a recent study reported that genetic ablation of nearly all Kiss1-expressing neurons (Kiss1 neurons) does not impair reproduction, arguing that neither Kiss1 neurons nor their products are essential for sexual maturation. We posited that only minute quantities of kisspeptin are sufficient to support reproduction. If this were the case, animals having dramatically reduced Kiss1 expression might retain fertility - testifying to the redundancy of Kiss1 neurons and their products. To test this hypothesis and to determine whether males and females differ in the required amount of kisspeptin needed for reproduction, we used a mouse (Kiss1-CreGFP) that has a severe reduction in Kiss1 expression. Mice that are heterozygous and homozygous for this allele (Kiss1(Cre/+) and Kiss1(Cre/Cre)) have 50% and 95% reductions in Kiss1 transcript, respectively. We found that although male Kiss1(Cre/Cre) mice sire normal-sized litters, female Kiss1(Cre/Cre) mice exhibit significantly impaired fertility and ovulation. These observations suggest that males require only 5% of normal Kiss1 expression to be reproductively competent, whereas females require higher levels for reproductive success.
Kisspeptins, the product of the KISS1 gene, play an essential role in the regulation of reproductive functions, acting primarily at the hypothalamic level of the gonadotropic axis. We detected polymorphisms of the goat KISS1 gene in 723 individuals from three goat breeds (Xinong Saanen, Guanzhong and Boer) by DNA pooling, PCR-RFLP, and DNA sequencing methods. We cloned the promoter sequence of this gene and found it to share high similarity with that of the bovine KISS1 promoter. Six TATA boxes were found in the goat KISS1 promoter region. Two novel SNPs (g.2124T>A and g.2270C>T) were identified in the intron 1 of KISS1 gene of all three goat breeds. The three goat breeds were in Hardy-Weinberg disequilibrium at g.2124T>A and g.2270C>T loci. The g.2124T>A and g.2270C>T loci were closely linked in the three goat breeds (r2 > 0.33). The g.2124T>A and g.2270C>T SNPs were significantly associated with litter size, and the C1 female goats had a larger litter size than did those with the other genotypes. These results extend the spectrum of genetic variation of the goat KISS1 gene, which contributes to our knowledge of goat genetic resources for breeding programs.
In the present study, the polymorphisms of kisspeptin (KiSS-1) gene were analyzed in 652 individuals from three goat breeds: Xinong Saanen goats (SG), Guanzhong goats (GZ) and Boer goats (BG). Three alleles (T, C and G) and four genotypes (TT, TC, CC and TG) were detected in the intron 2 of KiSS-1 gene by PCR-SSCP analysis. In addition, two single nucleotide polymorphisms (SNPs) – T2643C and 8bp base deletions (2677AGTTCCCC) were identified by DNA sequencing. The SNPs loci were in Hardy–Weinberg disequilibrium in three goat breeds (P < 0.05). After comparing genotypic distribution within three goat breeds, BG had conspicuous differences from SG and GZ (P < 0.001). Association of polymorphism with litter size was done in SG and GZ breeds, which showed to be associated with litter size in both goat breeds. The SNP in goat KiSS-1 gene had significant effects on litter size (P < 0.05). Therefore, these results suggest that KiSS-1 gene is a strong candidate gene that affects litter size in goats.
Ovulation in mammals is gated by a master circadian clock in the suprachiasmatic nucleus (SCN). GnRH neurons represent the converging pathway through which the brain triggers ovulation, but precisely how the SCN times GnRH neurons is unknown. We tested the hypothesis that neurons expressing kisspeptin, a neuropeptide coded by the Kiss1 gene and necessary for the activation of GnRH cells during ovulation, represent a relay station for circadian information that times ovulation. We first show that the circadian increase of Kiss1 expression, as well as the activation of GnRH cells, relies on intact ipsilateral neural input from the SCN. Second, by desynchronizing the dorsomedial (dm) and ventrolateral (vl) subregions of the SCN, we show that a clock residing in the dmSCN acts independently of the light-dark cycle, and the vlSCN, to time Kiss1 expression in the anteroventral periventricular nucleus of the hypothalamus and that this rhythm is always in phase with the LH surge. In addition, we show that although the timing of the LH surge is governed by the dmSCN, its amplitude likely depends on the phase coherence between the vlSCN and dmSCN. Our results suggest that whereas dmSCN neuronal oscillators are sufficient to time the LH surge through input to kisspeptin cells in the anteroventral periventricular nucleus of the hypothalamus, the phase coherence among dmSCN, vlSCN, and extra-SCN oscillators is critical for shaping it. They also suggest that female reproductive disorders associated with nocturnal shift work could emerge from the desynchronization between subregional oscillators within the master circadian clock.
KISS1R and its ligand, the kisspeptins, are key hypothalamic factors that regulate GnRH hypothalamic secretion and therefore the pubertal timing. During studies analysing KiSS1 as a candidate gene in pubertal onset disorders, two SNP and one nucleotide insertion were observed in a 23 nucleotides G-rich sequence located 65 nucleotides downstream of the stop codon. The polymorphisms formed four haplotypes. Biophysical experiments revealed the ability of this G-rich sequence to fold into G-quadruplex structures and demonstrated that the three DNA polymorphisms did not perturb the folding into G-quadruplex but affected G-quadruplex conformation. A functional luciferase reporter-based assay revealed functional differences between 3'UTR haplotypes. These data show that polymorphisms in a G-rich sequence of the 3'UTR of KISS1, able to fold into G-quadruplex structures, can modulate gene expression. They highlight the potential role of this G-quadruplex in the regulation of KISS1 expression and in the timing of pubertal onset.
Immotile, short-tail sperm defect (ISTS) expanded in the Finnish Yorkshire population in the end of 1990s. The causal mutation for this defect is a recent L1 insertion within the SPEF2 gene in chromosome 16. Even though all homozygous boars are eliminated from the population because of infertility, the amount of affected boars increased rapidly until marker-assisted selection against the defect was established. To elucidate the associated effects of the ISTS defect on production traits, we have investigated the association of the L1 insertion and PRLR haplotype with reproduction traits in the Finnish Yorkshire population. Two data sets including 357 sows and 491 AI-boars were genotyped for the presence of the L1 insertion and analysed for association with reproduction traits. A Proc Mixed procedure (SAS Inc) and a software package for analysing multivariate mixed models (DMU) were used to study the effect of polymorphisms on reproduction traits. The L1-insertion within SPEF2 gene was associated with litter size in the first parity. The SPEF2 gene is located adjacent to a candidate gene for litter size in the pig, PRLR. Haplotypes within PRLR exon 10 were analysed in data set of 93 AI-boars for the association with reproduction traits. However, no associations were detected within the analysed data set indicating that PRLR sequence variants are not the causal cause for the identified effect on litter size.
KISS-1 and GPR54 were regarded as key regulators for the puberty onset and fundamental gatekeepers of sexual maturation in mammals. To explore the possible association between variations in KISS-1 and GPR54 with sexual precocity, mutation screening of exon 1 of KISS-1 and exon 1, exon 3, and partial exon 5 of GPR54 was performed in a sexual precocious breed (Jining Grey goats) and sexual late-maturing breeds (Inner Mongolia Cashmere, Angora, and Boer goats) by PCR-SSCP. The results showed that five novel mutations were identified in exon 1 and partial exon 5 of GPR54 including C96 T, T173C, G176A, G825A, and C981 T. The Jining Grey goats with genotype BB or AB had 1.07 (P < 0.05) or 0.40 (P < 0.05) kids more than those with AA. The Jining Grey goats with genotype DD or CD had 1.80 (P < 0.05) or 0.55 (P < 0.05) kids more than CC, respectively. The present study preliminarily showed an association between alleles B and D of GPR54 with high litter size and sexual precocity in Jining Grey goats.
Metastasis is a major cause of death in cancer patients and involves a multistep process including detachment of cancer cells from a primary cancer, invasion of surrounding tissue, spread through circulation, re-invasion and proliferation in distant organs. KiSS-1 is a human metastasis suppressor gene, that suppresses metastases of human melanomas and breast carcinomas without affecting tumorigenicity. However, its gene product and functional mechanisms have not been elucidated. Here we show that KiSS-1 (refs 1, 4) encodes a carboxy-terminally amidated peptide with 54 amino-acid residues, which we have isolated from human placenta as the endogenous ligand of an orphan G-protein-coupled receptor (hOT7T175) and have named 'metastin'. Metastin inhibits chemotaxis and invasion of hOT7T175-transfected CHO cells in vitro and attenuates pulmonary metastasis of hOT7T175-transfected B16-BL6 melanomas in vivo. The results suggest possible mechanisms of action for KiSS-1 and a potential new therapeutic approach.
Mammalian reproduction depends on the coordinated expression of behavior with precisely timed physiological events that are fundamentally different in males and females. An improved understanding of the neuroanatomical relationships between sexually dimorphic parts of the forebrain has contributed to a significant paradigm shift in how functional neural systems are approached experimentally. This review focuses on the organization of interconnected limbic-hypothalamic pathways that participate in the neural control of reproduction and summarizes what is known about the developmental neurobiology of these pathways. Sex steroid hormones such as estrogen and testosterone have much in common with neurotrophins and regulate cell death, neuronal migration, neurogenesis, and neurotransmitter plasticity. In addition, these hormones direct formation of sexually dimorphic circuits by influencing axonal guidance and synaptogenesis. The signaling events underlying the developmental activities of sex steroids involve interactions between nuclear hormone receptors and other transcriptional regulators, as well as interactions at multiple levels with neurotrophin and neurotransmitter signal transduction pathways.
Metastin is encoded by a putative human metastasis suppressor gene KiSS-1, and is the cognate ligand of a G-protein-coupled receptor designated OT7T175. To study the physiological function(s) of metastin, we cloned rat and mouse KiSS-1 cDNAs both encoding 130-amino acid KiSS-1 proteins. Sequence analysis suggested that processing of the rat and mouse KiSS-1 proteins produces 52-amino-acid peptides, each with an amidated carboxyl terminal and with a single possible disulfide bond, corresponding to rat and mouse metastins. The carboxyl-terminal sequence of metastin, known to be essential for functional receptor interaction, was found to be highly conserved among humans and rodents. Real-time PCR analysis indicated that rat KiSS-1 mRNA showed the highest expression level in the cecum and colon. Since KiSS-1 mRNA and metastin are known to be abundant in human placenta, we further studied the localization of KiSS-1 and OT7T175 mRNAs in rat placenta by in situ hybridization. KiSS-1 and OT7T175 mRNAs were specifically detected in trophoblast giant cells at embryonic day 12.5, and the transcripts in the cells gradually decreased during placental maturation. These results suggest that metastin/OT7T175 signaling may participate in implantation of the mammalian embryo, placenta formation, and maintenance of pregnancy.
Increasing levels of circulating estradiol during the follicular phase of the ovarian cycle act on the brain to trigger a sudden and massive release of gonadotropin-releasing hormone (GnRH) that evokes the pituitary luteinizing hormone surge responsible for ovulation in mammals. The mechanisms through which estrogen is able to exert this potent "positive feedback" influence upon the GnRH neurons are beginning to be unravelled. Recent studies utilizing mouse models with global and cell-specific deletions of the different estrogen receptors (ERs) have shown that estrogen positive feedback is likely to use an indirect pathway involving the modulation of ERalpha-expressing neurons that project to GnRH neurons. Conventional tract tracing studies in rats, and experiments involving conditional pseudorabies virus tract tracing from GnRH neurons in the transgenic mouse, indicate that the dominant populations of ERalpha-expressing neuronal afferents to GnRH neurons reside in the anteroventral periventricular, median preoptic and periventricular preoptic nuclei. Together these estrogen-sensitive afferents to GnRH neurons form a periventricular continuum that can be referred to as rostral periventricular area of the third ventricle (RP3V) neurons. The neurochemical identity of some RP3V neurons has been determined and there is mounting evidence for important roles of glutamate, GABA, kisspeptin and neurotensin-expressing RP3V neurons in estrogen positive feedback. The definition of the key cluster of estrogen-sensitive neurons responsible for activating the GnRH neurons to evoke the GnRH surge (and ovulation) should be of substantial value to on-going efforts to understand the molecular and cellular basis of the estrogen positive feedback mechanism.
The kisspeptin/GPR54 pathway has been proven to be crucial in the process of puberty onset, yet the polymorphisms in the KISS1 gene and their relationships with central precocious puberty (CPP) have not been investigated. This study was performed to reveal the relationship between the gene and the disease.
272 Chinese Han girls diagnosed to be CPP patients were recruited as Case Group I, 43 unrelated African women as Case Group II, and 288 unrelated normal Chinese Han girls as Control Group. Polymorphism scans of the KISS1 gene were performed for the first time by bidirectional resequencing of the whole gene in a subset of the patients, and then by ligase detection reaction some of the polymorphisms identified were typed in the two groups and the respective haplotypes were constructed. The relationships of the typed polymorphisms and the haplotypes with CPP were evaluated by an association study between genotypes and phenotypes.
By resequencing, eight polymorphisms were identified, five of which were typed forming 18 haplotypes. Although one novel nonsynonymous single nucleotide polymorphism substituting one amino acid in kisspeptin (P110T) was found to be statistically related to the disease (P = 0.025), no further supporting evidence has yet been found. The other polymorphisms and all the haplotypes were not found to be related.
The polymorphism scanning and typing of KISS1 uncovered several potentially meaningful polymorphisms, but the conclusion was not solid and further studies are necessary for function validation of these polymorphisms.
Identification, in late 2003, of inactivating mutations of the G protein-coupled receptor GPR54 as causative factor for absence of puberty and hypogonadotropic hypogonadism in humans and mice was a major breakthrough in modern Neuroendocrinology, and drew considerable interest on the characterization of the roles of this receptor and its ligands (kisspeptins, encoded by the KiSS-1 gene) in the physiological control of essential facets of reproduction. After 3 years of intense research activity, kisspeptins are universally recognized as essential activators of the gonadotropic axis, with key roles in puberty onset and the control of gonadotropin secretion. While these fundamental functions are now well settled, novel aspects of kisspeptin/GPR54 physiology have emerged, including their involvement in the neuroendocrine control of ovulation and the metabolic gating of reproductive function. In addition, the 'comparative endocrinology' of this system has begun to be explored recently. These facets of kisspeptin/GPR54 function, as fundamental gatekeepers of reproduction, will be comprehensively reviewed herein.