[Show abstract][Hide abstract] ABSTRACT: Plant laccase (LAC) enzymes belong to the blue copper oxidase family and polymerize monolignols into lignin. Recent studies have established the involvement of microRNAs in this process; however, physiological functions and regulation of plant laccases remain poorly understood. Here, we show that a laccase gene, LAC4, regulated by a microRNA, miR397b, controls both lignin biosynthesis and seed yield in Arabidopsis. In transgenic plants, overexpression of miR397b (OXmiR397b) reduced lignin deposition. The secondary wall thickness of vessels and the fibres was reduced in the OXmiR397b line, and both syringyl and guaiacyl subunits are decreased, leading to weakening of vascular tissues. In contrast, overexpression of miR397b-resistant laccase mRNA results in an opposite phenotype. Plants overexpressing miR397b develop more than two inflorescence shoots and have an increased silique number and silique length, resulting in higher seed numbers. In addition, enlarged seeds and more seeds are formed in these miR397b overexpression plants. The study suggests that miR397-mediated development via regulating laccase genes might be a common mechanism in flowering plants and that the modulation of laccase by miR397 may be potential for engineering plant biomass production with less lignin.
[Show abstract][Hide abstract] ABSTRACT: microRNAs (miRNAs), a class of small, endogenous, noncoding RNAs, are uncovered to play greatly expanded roles in a variety of plant developmental processes by gene silencing through inhibiting translation or promoting the degradation of target mRNAs. In virtue of their ability to inactivate either specific genes or entire gene families, artificial miRNAs function as dominant suppressors of gene activity when brought into a plant. Moreover, artificial target mimics are applied for the reduction of specific miRNA activity. Consequently, miRNA-based manipulations have emerged as promising new approaches for the improvement of crop plants. This action includes the development of breeding strategies and the genetic modification of agronomic traits. Herein, we describe the current miRNA-based plant engineering approaches, and their advantages and challenges are also stated.
[Show abstract][Hide abstract] ABSTRACT: The whole structure of higher plants is generated dynamically throughout the life cycle by the activity of stem cell niches at the apex of shoot and root. Hormone molecules and many transcription factors cooperate to balance the stem cell maintenance and differentiation. It is becoming increasingly clear that microRNA (miRNA) molecules are also participants in these processes. Here, we highlight the advances that have been made in regarding the roles of miRNAs in plant stem cell control. These advances provide a framework for our understanding of how signals are integrated to specify and position the stem cell niches in plants.
Biochemical and Biophysical Research Communications 06/2011; 409(3):363-6. DOI:10.1016/j.bbrc.2011.04.123 · 2.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Small RNAs constitute a new and unanticipated layer of gene regulation present in the three domains of life. In plants, all organs are ultimately derived from a few pluripotent stem cells localized in specialized structures called apical meristems. The development of meristems involves a coordinated balance between undifferentiated growth and differentiation, a phenomenon requiring a tight regulation of gene expression. We used in vitro cultured embryogenic calli as a model to investigate the roles of meristem-associated small RNAs. Using high throughput sequencing, we sequenced 20 million short reads with size of 18-30 nt from rice undifferentiated and differentiated calli. We confirmed 50 known microRNA families, representing one third of annotated rice microRNAs. Using a specific computational pipeline for plant microRNA identification, we identified 24 novel microRNA families. Among them, 53 microRNA or microRNA* sequences appear to vary in expression between differentiated and undifferentiated calli, suggesting a role in meristem development. Our analysis also revealed a new class of plant small RNAs derived from 5' or 3' ends of mature tRNA analogous to the tRFs in human cancer cell. We independently verified the expression of these small RNAs from 5' end of mature tRNA using qRT-PCR.
[Show abstract][Hide abstract] ABSTRACT: The choice of the tumor antigen preparation used for dendritic cell (DC) loading is important for optimizing DC vaccines. In the present study, we compared DCs pulsed with hepatocellular carcinoma (HCC) total RNA or cell lysates for their capacity to activate T cells. We showed here that HCC total RNA pulsed-DCs induced effector T lymphocyte responses which showed higher killing ability to HCC cell lines, as well as higher frequency of IFN-γ producing of CD4+ and CD8+ T cells when compared with lysate pulsed-DCs. Both of RNA and lysate loading did not influence the changes of mature DC phenotype and the capacity of inducing T cell proliferation. However, HCC lysate loading significantly inhibited the production of inflammatory cytokines IL-12p70, IFN-γ and enhanced the secretion of anti-inflammatory cytokines IL-10 of mature DCs. Our results indicated that DCs loaded with HCC RNA are superior to that loaded with lysate in priming anti-HCC CTL response, suggesting that total RNA may be a better choice for DCs-based HCC immunotherapy.
International journal of biological sciences 10/2010; 6(7):639-48. · 4.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: MicroRNAs (miRNAs) are small, endogenous, noncoding RNAs that negatively modulate the expression of genes by inhibiting translation or by promoting the degradation of target mRNAs. miRNAs are now known to have greatly expanded roles in a variety of plant developmental processes, in signal transduction, and in the response to environmental stress and pathogen invasion. Because of their ability to inactivate either specific genes or entire gene families, artificial miRNAs function as dominant suppressors of gene activity when brought into a plant. Consequently, miRNA-based manipulations have emerged as promising new approaches for the improvement of crops. This includes the development of breeding strategies and the genetic modification of agronomic traits. Herein, we highlight new findings regarding the roles of miRNAs in plant traits, and describe the current miRNA-based plant engineering approaches. Finally, we consider the feasibility of modulating current approaches to address future challenges such as breeding programs to increase crop yield.
[Show abstract][Hide abstract] ABSTRACT: The Kiss1/Kiss1r system is a component of the hypothalamus-pituitary-gonadal (HPG) axis, which plays a crucial role in regulating gonadotropins and gonadotropin-releasing hormone. The sex reversal process is a special reproductive phenomenon regulated by the HPG axis. To better understand the neuroendocrine mechanisms of sex reversal, cDNAs encoding kiss2 and kiss1ra have been cloned and functionally characterized from the orange-spotted grouper Epinephelus coioides, a protogynous hermaphroditic teleost. The core mature peptide (Kiss2-10) of grouper Kiss2 shared high similarity to other KISS orthologs. In phylogenetic analyses, the grouper Kiss was clustered with the teleost Kiss2 clade and termed grouper kiss2. The predicted amino acid sequence of grouper kiss1ra contained three putative glycosylation sites at its N-terminus, showing high similarity to that of other teleosts. Synthesized Kiss2-10 was able to functionally interact with Kiss1ra in cultured COS-7 cells to trigger downstream signaling. Both kiss2 and kiss1ra mRNAs were expressed in all tissues examined, with highest levels in the olfactory bulb and moderate levels in the hypothalamus among brain areas and highest levels in ovary among peripheral tissues. Intraperitoneal injection of Kiss2-10 significantly increased gnrh1 mRNA levels in hypothalamus and follicle-stimulating hormone beta (fshb) mRNA levels in the pituitary at 6 and 12 h postinjection. During the process of sex reversal induced by 17 alpha-methyltestosterone (MT), kiss2 and kiss1ra mRNA expression were significantly decreased in the first week, but kiss2 increased in the fourth week, in accordance with the expression pattern of gnrh1 mRNA in the grouper hypothalamus. This is the first description of the Kiss2/Kiss1ra system during MT-induced sex reversal in orange-spotted grouper.
Biology of Reproduction 04/2010; 83(1):63-74. DOI:10.1095/biolreprod.109.080044 · 3.32 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To analyze the incidence of benign lesions in Chinese patients undergoing nephrectomies for renal masses identified as localized renal cell carcinoma (RCC) in preoperative imaging.
Between 1999 and 2007, 303 patients (112 female, 191 male) with presumed localized RCC underwent nephrectomy (234 radical nephrectomies and 69 partial nephrectomies). Preoperative computed tomography images and pathological findings were reviewed and analyzed.
Pathological examinations revealed 31 (10.2%) benign lesions in the 303 patients. Among these 31 benign lesions, 15 (5.0%) were angiomyolipomas (AML) and only four (1.3%) were oncocytomas. Significantly, 20 (17.9%) of the 112 female patients had benign lesions compared with 11 (5.8%; P = 0.001) male patients. Benign renal lesions were found in five (25.0%) of the 20 patients with renal masses smaller than 2 cm, 13 (13.0%) of the 100 patients with renal masses 2-4 cm in size and 13 (7.1%) of the 183 patients with renal masses larger than 4 cm.
Patients in the present study population show a low incidence of benign renal lesions, approximately half of them being AML. Female patients and patients with renal masses smaller than 4 cm are more likely to have benign renal lesions.
International Journal of Urology 03/2010; 17(6):517-21. DOI:10.1111/j.1442-2042.2010.02525.x · 2.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To explore the etiologic relationship of prostate cancer and environmental and genetic polymorphism in southern China
A hospital-based and 1:1 matched case-control study was conducted. A total of 142 matched pairs of subjects were investigated in this study. The blood samples were collected from 85 cases of prostate cancer and 82 controls of other diseases after informing consent. The CYP1A1, CYP17 and AR genes were analyzed by using the method of PCR, PCR-RFLP. The data were analyzed with conditional logistic regression model.
An increased risk of prostate cancer development was observed with the early first spermatorrhea (age < 18) (OR = 2.90, 95% CI: 1.76 - 4.80), early first sexual intercourse (age < or = 24) (OR = 2.38, 95% CI: 1.14 - 4.96), frequent sexual intercourse before 35 year old (OR = 1.80, 95% CI: 1.19 - 2.70), family history of cancer (OR = 2.70, 95% CI: 1.31 - 5.58), more intake of pork (OR =2.27, 95% CI: 1.38 - 3.70). Factors in lowing the risks were the fruit intake and drinking of green tea by OR value at 0.25 (95% CI: 0.08 - 0.75) and 0.52 (95% CI: 0.28 -0.96) respectively. CYP17 A1/A2 and CYP17 A2/A2 genotypes were related with a high risk of prostate cancer and OR values of 1.78 (95% CI: 0.70 - 4.53) and 2.57 (95% CI: 0.91 - 7.25) respectively. Study also showed that there was an interaction between CYP17 polymorphisms and early first spermatorrhea and family cancer history related to the risk of prostate cancer with OR value at 13.35 (95% CI: 1.58 - 113.00) and 4.01 (95% CI: 1.22 - 13.17) respectively.
Sexual intercourse, dietary intake and family cancer history should be related to prostate cancer occurrence. CYP17 polymorphism might be associated with a high risk of prostate cancer. It suggests that there are multiple environmental and genetic factors to the prostate cancer.
Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine] 07/2009; 43(7):581-5.
[Show abstract][Hide abstract] ABSTRACT: MicroRNAs (miRNAs) are small non-coding regulatory RNAs that regulate gene expression in plants by targeting mRNAs for cleavage or translational repression. Over the past years, miRNAs have been validated to play crucial roles in plant growth and development. Recent researches have witnessed the identification of intersection between miRNAs pathways and phytohormone responses, which improves our understanding of miRNAs and hormone action in developmental control. In this review, we highlight the progress on the current known relationship of miRNAs with phytohormone signaling, and the potential roles of some specific miRNAs in hormone signaling were also discussed.
Biochemical and Biophysical Research Communications 05/2009; 384(1):1-5. DOI:10.1016/j.bbrc.2009.04.028 · 2.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Twenty-two conserved miRNAs were chosen to investigate the expression pattern in response to phytohormone treatments, in which the effects of five classic plant hormone stresses were surveyed in Oryza sativa. The results showed that 11 miRNAs were found to be dysregulated by one or more phytohormone treatments. The target genes of these miRNAs were validated in vivo and their expression profiling were revealed. We also analyzed the promoter regions of the 22 conserved miRNAs for phytohormone-responsive elements and the existence of the elements provided further evidences supporting our results. These findings enable us to further investigate the role of miRNAs in phytohormone signaling.
[Show abstract][Hide abstract] ABSTRACT: Prostate cancer is a common cancer in American and European men. The incidence of prostate cancer is low in China, but increases year by year. The previous etiologic studies on prostate cancer in China were mainly conducted in Shanghai, Wuhan, and Beijing, but rarely in Guangdong. This study was to explore the etiologic correlations of prostate cancer to sexual and marital factors and family history of cancers among Cantonese.
A hospital-based case-control study was conducted from 2005 through 2006 in 4 affiliated hospitals of Sun Yat-sen University. The cases and controls were matched by age (+/-5 years), sex, race and resident location. All the subjects were interviewed by experienced investigators. The data were analyzed with conditional Logistic regression model.
A total of 186 subjects were investigated in this study, including 62 patients with prostate cancer, 62 with benign prostatic hyperplasia (BPH) and 62 with other diseases as controls. When BPH was referred to, an increased prostate cancer risk was seen for the men with the age at the first spermatorrhea of less than 15 as compared with those with the age of over 18 [odds ratio (OR) = 6.37, 95% confidence interval (CI) = 0.63-63.95]. The men with the first sexual activity in early age were at higher risk of prostate cancer than those in the age of over 30 (in the age of 20-24, OR = 2.25, 95% CI = 0.75-6.71; in the age of 25-29, OR = 2.34, 95% CI= 0.89-6.13). A decreased risk of prostate cancer was found among those men who lost sexual activity after 60 years (in the age of 60-69, OR = 0.51, 95% CI = 0.20-1.27; in the age of over 70, OR = 0.31, 95% CI = 0.08-1.24). When other diseases were referred to, the men with 1 first-degree relative suffered from cancer had greater risk to develop prostate cancer than those without family history of cancers (OR = 2.25, 95% CI = 0.69-7.31). Compared with the age of over 30, an earlier age of the first sexual activity increased the risk of prostate cancer (in the age of less than 20, OR = 5.07, 95% CI = 0.50-51.46); A decreased risk of prostate cancer was also found in the men without sexual activities after 60 years (in the age of 60-69, OR = 0.55, 95% CI = 0.24-1.26; in the age of over 70, OR = 0.41, 95% CI = 0.11-1.47).
Earlier age of the first spermatorrhea and the first sexual activity may increase the risk of prostate cancer. Positive family history of cancers in first-degree relatives can promote the incidence of prostate cancer.
Ai zheng = Aizheng = Chinese journal of cancer 05/2007; 26(5):484-8. · 2.16 Impact Factor