-
[show abstract]
[hide abstract]
ABSTRACT: Myogenic regulatory factor Myf5 plays important roles in muscle development. In zebrafish myf5, a microRNA (miR), termed miR-3906 or miR-In300, was reported to silence dickkopf-3-related gene (dkk3r or dkk3a), resulting in repressing myf5 promoter activity. However, the membrane receptor which interacts with ligand Dkk3a to control myf5 expression through signal transduction remains unknown. To address this question, we applied immunoprecipitation and LC-MS/MS mass spectrometry to screen putative membrane receptors of Dkk3a, and Integrinα6b (Itgα6b) was finally identified. To further confirm this, we employed cell-surface binding assays which showed that Dkk3a and Itgα6b co-expressed at the cell membrane of HEK-293T cells. Crosslinking immunoprecipitation data also showed high affinity of Itgα6b for Dkk3a. We further proved that the beta-propeller repeated domains of Itgα6b are key segments bound by Dkk3a. Moreover, when dkk3a and itgα6b mRNAs were co-injected into embryos, luciferase activity was upregulated four-fold greater than that of control embryos. In contrast, the luciferase activities of dkk3a-knockdown embryos co-injected with itgα6b mRNA and itgα6b-knockdown embryos co-injected with dkk3a mRNA were decreased in a manner similar to control embryos, respectively. Knockdown of itgα6b resulted in abnormal somite shape, fewer somitic cells, weaker, or absent, myf5 expression, and reduced protein level of phosphorylated p38a in somites. These defective phenotypes of trunk muscular development were similar to those of dkk3a-knockdown embryos. We demonstrated that the secreted ligand Dkk3a binds to the membrane receptor Itgα6b, which increases the protein level of phosphorylated p38a and activates myf5 promoter activity of zebrafish embryos during myogenesis.
Journal of Biological Chemistry 09/2012; · 4.77 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Arl6ip1 has been reported to play a role in ocular development, but its regulatory function as it relates to proliferation is unclear. Therefore, this study aimed to evaluate how Arl6ip1 may regulate the proliferative behavior of retinal progenitor cells during zebrafish embryogenesis.
Arl6ip1 was specifically knocked down by introducing morpholino nucleic acid oligomers. The DNA content of cells dissociated from morphant eyes was analyzed by fluorescence-activated cell sorting (FACS). Retinal cells in the S- and late G2/M-phase were detected by labeling with BrdU and then immunostaining with anti-BrdU antibody and by immunostaining with phospho-histone H3 antibody, respectively. We also examined the expressions of shh,p57kip2, and cyclin D1 in retinas of experimental animals. The bidirectional plasmid pGFP:HSE:p57kip2 was used to rescue the defect in cell cycle exit.
FACS analysis showed that the >2C DNA content per cell in the eyes of arl6ip1 morphants was 2-fold greater than that of the wild type. Following functional Arl6ip1 knockdown, anti-BrdU- and anti-phospho-histone H3-positive signals were higher and the retinal progenitors kept expressing cyclin D1 but not shh or p57kip2, suggesting that eye progenitor cells remained in an early progenitor state and could not exit the cell cycle to progress to differentiation. Interestingly, overexpression of p57kip2, which enables exit from the cell cycle, led to a reduction of anti-BrdU-positive signals in the retinas of arl6ip1 morphants.
Arl6ip1 not only affects signals controlling eye development but also plays an important role in the proliferation of retinal progenitor cells.
Cells Tissues Organs 01/2012; 196(2):161-74. · 2.20 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Although the embryonic expression pattern of ADP ribosylation factor-like 6 interacting protein 1 (Arl6ip1) has been reported, its function in neural crest development is unclear.
We found that knockdown of Arl6ip1 caused defective embryonic neural crest derivatives that were particularly severe in craniofacial cartilages. Expressions of the ectodermal patterning factors msxb, dlx3b, and pax3 were normal, but the expressions of the neural crest specifier genes foxd3, snai1b, and sox10 were greatly reduced. These findings suggest that arl6ip1 is essential for specification of neural crest derivatives, but not neural crest induction. Furthermore, we revealed that the streams of crestin- and sox10-expressing neural crest cells, which migrate ventrally from neural tube into trunk, were disrupted in arl6ip1 morphants. This migration defect was not only in the trunk neural crest, but also in the enteric tract where the vagal-derived neural crest cells failed to populate the enteric nervous system. We found that this migration defect was induced by dampened Shh signaling, which may have resulted from defective cilia. These data further suggested that arl6ip1 is required for neural crest migration. Finally, by double-staining of TUNEL and crestin, we confirmed that the loss of neural crest cells could not be attributed to apoptosis.
Therefore, we concluded that arl6ip1 is required for neural crest migration and sublineage specification.
PLoS ONE 01/2012; 7(3):e32899. · 4.09 Impact Factor
-
Ying-Hsin Chen,
Hung-Chieh Lee,
Ren-Jun Hsu,
Ta-Yuan Chen,
Yu-Kai Huang,
Hao-Chan Lo,
Sheng-Chuan Hu,
Horng-Jyh Harn,
Jing-Ren Jeng,
Chi-Kuang Sun,
Shinn-Zong Lin, Huai-Jen Tsai
[show abstract]
[hide abstract]
ABSTRACT: Amiodarone is a class D drug given to treat arrhythmia, including pregnant women, but its effects on the developing heart have not been studied. Although some studies have suggested that this drug is safe for fetuses, they have been conducted on mothers with fetuses at or beyond six months of gestational age.
The occurrence of valve defect was positively proportional to Amiodarone concentrations over 9 μM, but not lower than 6 μM. Ectopic overexpression of versican was observed at the atrioventricular canal of the Amiodarone-treated embryos at 15 μM (EC(50)). VE-cadherin (cdh5), normally downregulated at the endocardial cushion, was also ectopically overexpressed in the Amiodarone-treated embryos. Knockdown of either versican or cdh5 in the Amiodarone-treated embryos could rescue the valve defect caused by Amiodarone.
By inducing versican ectopical overexpression, leading, in turn, to cdh5 ectopical overexpression, Amiodarone treatment causes failure of cardiac valve formation in zebrafish embryos.
Reproductive Toxicology 12/2011; 33(2):233-44. · 3.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Upstream open reading frame (uORF)-mediated translational inhibition is important in controlling key regulatory genes expression. However, understanding the underlying molecular mechanism of such uORF-mediated control system in vivo is challenging in the absence of an animal model. Therefore, we generated a zebrafish transgenic line, termed huORFZ, harboring a construct in which the uORF sequence from human CCAAT/enhancer-binding protein homologous protein gene (huORF(chop)) is added to the leader of GFP and is driven by a cytomegalovirus promoter. The translation of transgenic huORF(chop)-gfp mRNA was absolutely inhibited by the huORF(chop) cassette in huORFZ embryos during normal conditions, but the downstream GFP was only apparent when the huORFZ embryos were treated with endoplasmic reticulum (ER) stresses. Interestingly, the number and location of GFP-responsive embryonic cells were dependent on the developmental stage and type of ER stresses encountered. These results indicate that the translation of the huORF(chop)-tag downstream reporter gene is controlled in the huORFZ line. Moreover, using cell sorting and microarray analysis of huORFZ embryos, we identified such putative factors as Nrg/ErbB, PI3K and hsp90, which are involved in huORF(chop)-mediated translational control under heat-shock stress. Therefore, using the huORFZ embryos allows us to study the regulatory network involved in human uORF(chop)-mediated translational inhibition.
Nucleic Acids Research 08/2011; 39(20):e139. · 8.03 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Myf5 is a myogenic regulatory factor that functions in myogenesis. An intronic microRNA, miR-In300, located within zebrafish myf5 intron I, has been reported to silence myf5 through the targeting of dickkopf-3-related gene (dkk3r). However, the molecular mechanism underlying the control of myf5 expression by dkk3r is unknown. By injecting dkk3r-specific morpholino-oligonucleotide (dkk3r-MO) to knock down Dkk3r, we found that the phosphorylated p38a protein was reduced. Knockdown of p38a resulted in malformed somites and reduced myf5 transcripts, which photocopied the defects induced by injection of dkk3r-MO. To block the MAPK pathway, phosphorylation of p38 was inhibited by introduction of SB203580, which caused the down-regulation of myf5 expression. The GFP signal was dramatically decreased in somites when we injected p38a-MO into embryos derived from transgenic line Tg(myf5(80K):GFP), in which the GFP was driven by the myf5 promoter. Although these p38a-MO-induced defects were rescued by co-injection with p38a mRNA, they were not rescued with p38a mRNA containing a mutation at the phosphorylation domain. Moreover, overexpression of Smad2 or Smad3a enhanced myf5 expression, but the defects induced by the dominant negative form of either Smad2 or Smad3a equaled those of embryos injected with either dkk3r-MO or p38a-MO. These results support the involvement of Smad2·Smad3a in p38a mediation. Overexpression of Smad4 enabled the rescue of myf5 defects in the dkk3r-MO-injected embryos, but knockdown of either dkk3r or p38a caused Smad4 protein to lose stability. Therefore, we concluded that Dkk3r regulates p38a phosphorylation to maintain Smad4 stability, in turn enabling the Smad2·Smad3a·Smad4 complex to form and activate the myf5 promoter.
Journal of Biological Chemistry 02/2011; 286(8):6855-64. · 4.77 Impact Factor
-
An-Bang Wang,
Chia-Wei Cheng,
I-Chun Lin,
Fei-Yau Lu, Huai-Jen Tsai,
Chiu-Chun Lin,
Chun-Hui Yang,
Po-Ting Pan,
Chen-Chi Kuan,
Yen-Chih Chen,
Yi-Wei Lin,
Chih-Ning Chang,
Yi-Hung Wu,
Tetuko Kurniawan,
Chii-Wann Lin,
Andrew M Wo,
Lin-Chi Chen
[show abstract]
[hide abstract]
ABSTRACT: In the conventional bench-top approach, the DNA recombination process is time- and effort-consuming due to laborious procedures lasting from several hours to a day. A novel DNA selection and direct extraction process has been proposed, integrated and tested on chip. The integrative microfluidic chip can perform the whole procedure of DNA recombination, including DNA digestion, gel electrophoresis, DNA extraction and insert-vector ligation within 1 h. In this high-throughput design, the manual gel cutting was replaced by an automatic processing system that performed high-quality and high-recovery efficiency in DNA extraction process. With no need of gel-dissolving reagents and manipulation, the application of selection and direct extraction process could significantly eliminate the risks from UV and EtBr and also facilitate DNA recombination. Reliable output with high success rate of cloning has been achieved with a significant reduction in operational hazards, required materials, efforts and time.
Electrophoresis 02/2011; 32(3-4):423-30. · 3.30 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We developed a simple, direct, and cost-effective approach to search for the most likely target genes of a known miRNA in vitro. We term this method "Labeled microRNA (miRNA) pull-down assay system," or LAMP. Briefly, the pre-miRNA is labeled with digoxigenin (DIG), mixed with cell extracts, and immunoprecipitated by anti-DIG antiserum. We concluded that LAMP is an experimental approach for high-throughput identification of the target gene of known miRNAs from both Caenorhabditis elegans and zebrafish (Danio rerio), yielding fewer false-positive results than those produced by using only the bioinformatics approach.
Methods in molecular biology (Clifton, N.J.) 01/2011; 764:241-7.
-
[show abstract]
[hide abstract]
ABSTRACT: Although the crustacean Artemia has been commonly used as an experimental organism and served as a live bait feed for aquaculture, gene transfer system on Artemia sp. to generate stable lines is not well developed. In this study, we optimized a condition for cyst-eletroporation and generated stable lines of transgenic A. sinica. Two expression plasmids directed by the hybrid promoters of cytomegalovirus (CMV) and medaka β-actin (Mβ) were co-electroporated on decapsulated cysts: pCMV-Mβ-GFP contained GFP reporter gene and pCMV-Mβ-ypGH contained yellowfin porgy GH (ypGH) cDNA. We examined the GFP shown in the Artemia larvae and found that the expression rate was 13.3% (3,219 out of 24,054 examined). We then chose 200 G0 founders which strongly expressed GFP to generate transgenic lines. Homozygotic strains derived from F4 generation of each transgenic line, A3 and A8, were obtained. We proved that transgenic lines A3 and A8 also harbored pCMV-Mβ-ypGH and produced recombinant ypGH with a concentration of 0.089 and 0.032 μg per 50 homozygotic nauplii, respectively. Ten live Artemia nauplii were fed daily to zebrafish larvae during 25 to 35 days of post-fertilization. The average body length gain rates of zebrafish larvae fed transgenic Artemia were 16-20% greater than those of control group, indicating the exogenous ypGH produced by transgenic Artemia is functional. Therefore, we concluded that the transgenesis on Artemia is developed, and transgenic Artemia might be highly potentially useful as a new bioreactor material for application in aquaculture and biological researches.
Transgenic Research 01/2011; 20(5):1099-111. · 2.75 Impact Factor
-
Developmental Biology 08/2010; 344(1):490. · 4.07 Impact Factor
-
Developmental Biology 08/2010; 344(1):490. · 4.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A strong, negative cis-element located at the first intron +502/+835 (I300) of zebrafish myf5 has been reported. To elucidate the molecular mechanism underlying this repression network, we microinjected zebrafish single-cell embryos with I300 RNA, resulting in the dramatic reduction of luciferase activity driven by the myf5 promoter. Within this I300 segment, we identified an intronic microRNA (miR-In300) located at +609/+632 and found that it was more highly expressed in the older mature somites than those newly formed, which negatively correlated with the distribution of zebrafish myf5 transcripts. We proved that miR-In300 suppressed the transcription of myf5 through abolishing myf5 promoter activity, and we subsequently identified the long isoform of the Dickkopf-3 gene (dkk3) as the target gene of miR-In300. We further found that injection of the dkk3-morpholinos (MOs) resulted in downregulation of myf5 transcripts in somites, whereas co-injection of myf5 mRNA with dkk3-MO1 enabled rescue of the defects induced by dkk3-MO1 alone. Finally, injection of miR-In300-MO enhanced both myf5 transcripts in somites and the level of Dkk3 protein in zebrafish embryos. Based on these findings, we concluded that miR-In300 binds to its target gene dkk3, which inhibits the translation of dkk3 mRNA and, in turn, suppresses zebrafish myf5 promoter activity.
Nucleic Acids Research 03/2010; 38(13):4384-93. · 8.03 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Zebrafish (Danio rerio) was used as a bioreactor to produce bovine lactoferricin (LFB), which has wide-ranging antimicrobial activity. We constructed an expression plasmid in which LFB was fused with green fluorescent protein (GFP) and driven by zebrafish beta-actin promoter. After microinjection, six transgenic founders were screened on the basis of GFP appearance. Among them, a stable ZBL-5 line was selected by the ubiquitous and strong expression of GFP. Using PCR and Western blot analysis, we confirmed that the recombinant LFB-GFP protein was produced by the F2 progeny derived from the ZBL-5 line. The bactericidal agar plate assay proved that the functional domain of LFB was released from the LFB-GFP fusion protein, resulting in strong bactericidal activity against Escherichia coli, Edwardsiella tarda and Aeromonas hydrophila. Furthermore, adult zebrafish were given one feeding of fifty 72-hpf transgenic embryos. The treated fish were then immersed in freshwater containing 1 x 10(5) CFU ml(-1)E. tarda for 7 days. The survival rate of the treated zebrafish was significantly higher than that of fish fed with fifty wild-type embryos (75 +/- 12.5% versus 4 +/- 7.2%). This line of evidence suggested that pathogen resistance can be enhanced by using transgenic embryos containing LFB-GFP as a food supplement for fish, while, at the same time, reducing the demand of chemical antibiotics.
Fish & Shellfish Immunology 11/2009; 28(3):419-27. · 3.32 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The transcription factor FoxD5 is expressed in the paraxial mesoderm of zebrafish. However, the roles of FoxD5 in anterior pre-somitic mesoderm (PSM) during somitogenesis are unknown. We knocked down FoxD5 in embryos, which resulted in defects of the newly formed somites, including loss of the striped patterns of anterior-posterior polarity genes deltaC, notch2, notch3 and EphB2a, as well as the absence of mespa expression in S-I. Also, the expression of mespb exhibited a 'salt and pepper' pattern, indicating that FoxD5 is necessary for somite patterning in anterior PSM. Embryos were treated with SU5402, an Fgf receptor (FGFR) inhibitor, resulting in reduction of FoxD5 expression. This finding was consistent with results obtained from Tg(hsp70l:dnfgfr1-EGFP)pd1 embryos, whose dominant-negative form of FGFR1 was produced by heat-induction. Loss of FoxD5 expression was observed in the embryos injected with fgf3-/fgf8-double-morpholinos (MOs). Excessive FoxD5 mRNA could rescue the defective expression levels of mespa and mespb in fgf3-/fgf8-double morphants, suggesting that Fgf signaling acts as an upstream modulator of FoxD5 during somitogenesis. We concluded that FoxD5 is required for maintaining anterior-posterior polarity within a somite and that the striped pattern of FoxD5 in anterior PSM is mainly regulated by Fgf. An Fgf-FoxD5-Mesps signaling network is therefore proposed.
Developmental Biology 10/2009; 336(2):232-45. · 4.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Mutations of cardiac troponin C (cTnC) can cause dilated cardiomyopathy in humans.
Plasmids were constructed such that the reverse tetracycline-controlled transactivator (rtTA) was driven by the cardiac myosin light chain 2 promoter. This heart-specific rtTA bound another bidirectional promoter to express the green fluorescence protein reporter gene and the antisense RNA of cTnC in the presence of doxycycline. A transgenic line of zebrafish (CA17) with cTnC dysfunction was also generated. The heart rates of the embryos in the CA17 line were significantly slower than those of embryos in the control T03 transgenic line at 6 and 12 days post fertilization (dpf). In the CA17 line, cardiac chambers in the F2 embryos were significantly greater and the ventricular ejection fraction was lower than those in the T03 at both 6 and 12 dpf. The mortality rate of F2 adult fish of the CA17 line was also significantly higher (P<0.001).
Using conditional expression of antisense RNA of zebrafish cTnC, a new animal model with phenotypes simulating dilated cardiomyopathy has been created.
Circulation Journal 07/2009; 73(9):1691-7. · 3.77 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Transcription factor Six1a plays important roles in morphogenesis, organogenesis, and cell differentiation. However, the role of Six1a during zebrafish cranial muscle development is still unclear. Here, we demonstrated that Six1a was required for sternohyoideus, medial rectus, inferior rectus, and all pharyngeal arch muscle development. Although Six1a was also necessary for myod and myogenin expression in head muscles, it did not affect myf5 expression in cranial muscles that originate from head mesoderm. Overexpression of myod enabled embryos to rescue all the defects in cranial muscles induced by injection of six1a-morpholino (MO), suggesting that myod is directly downstream of six1a in controlling craniofacial myogenesis. However, overexpression of six1a was unable to rescue arch muscle defects in the tbx1- and myf5-morphants, suggesting that six1a is only involved in myogenic maintenance, not its initiation, during arch muscle myogenesis. Although the craniofacial muscle defects caused by pax3-MO phenocopied those induced by six1a-MO, injection of six1a, myod or myf5 mRNA did not rescue the cranial muscle defects in pax3 morphants, suggesting that six1a and pax3 do not function in the same regulatory network. Therefore, we proposed four putative regulatory pathways to understand how six1a distinctly interacts with either myf5 or myod during zebrafish craniofacial muscle development.
Developmental Biology 06/2009; 331(2):152-66. · 4.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We developed a simple, direct and cost-effective approach to search for the most likely target genes of a known microRNA (miRNA) in vitro. We term this method 'labeled miRNA pull-down (LAMP)' assay system. Briefly, the pre-miRNA is labeled with digoxigenin (DIG), mixed with cell extracts and immunoprecipitated by anti-DIG antiserum. When the DIG-labeled miRNA and bound mRNA complex are obtained, the total cDNAs are then subcloned and sequenced, or RT-PCR-amplified, to search for the putative target genes of a known miRNA. After successfully identifying the known target genes of Caenorhabditis elegans miRNAs lin-4 and let-7 and zebrafish let-7, we applied LAMP to find the unknown target gene of zebrafish miR-1, which resulted in the identification of hand2. We then confirmed hand2 as a novel target gene of miR-1 by whole-mount in situ hybridization and luciferase reporter gene assay. We further validated this target gene by microarray analysis, and the results showed that hand2 is the top-scoring among 302 predicted putative target genes. We concluded that LAMP is an experimental approach for high-throughput identification of the target gene of known miRNAs from both C. elegans and zebrafish, yielding fewer false positive results than those produced by using only the bioinformatics approach.
Nucleic Acids Research 06/2009; 37(10):e77. · 8.03 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Troponin I (TnnI), a constituent of the troponin complex on the thin filament, providers a calcium-sensitive switch for striated muscle contraction. Cardiac TnnI is, therefore, a highly sensitive and specific marker of myocardial injury in acute coronary syndromes. The TnnI gene, which has been identified in birds and mammals , encodes the isoforms expressed in cardiac muscle fast skeletal muscle and slow skeletal muscle. However, very little is known about the TnnI gene in lower vertebrates. Here, we cloned and characterized the molecular structures and expression patterns of three types of zebrafish tnni genes: tnni1, tnni2, and tnn-HC (Heart and craniofacial). Based on the unrooted radial gene tree analysis of the TnnI gene among vertebrates, the zebrafish Tnni1 and TnnI2 we cloned were homologous of the slow muscle TnnI1 and fast muscle TnnI2 of other vertebrates, respectively. In addition, reverse transcription-polymerase chain reaction (RT-PCR) and whole-mount in situ hybridization demonstrated that zebrafish tnni1 and tnni2 transcripts were not detectable in the somites until 16 h post-fertilization (hpf), after which they were identified as slow-and fast muscle-specific, respectively . Interestingly, tnni-HC, a novel tnni isoform of zebrafish was expressed exclusive in heart during early cardiogenesis as 16 hpf, but then extended its expression in craniofacial muscle after 48 hpf. Thus, using zebrafish as our system model, it is suggested that the results, as noted above, may provide more insight into the molecular structure and expression pattens of the lower vertebrate TnnI gene.
Gene Expression Patterns 03/2009; 9(5):348-56. · 2.02 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Nkx2.7 is the tinman-related gene, as well as orthologs of Nkx2.5 and Nkx-2.3. Nkx2.7 and Nkx2.5 express in zebrafish heart fields of lateral plate mesoderm. The temporal and spatial expression patterns of Nkx2.7 are similar to those of Nkx2.5, but their functions during cardiogenesis remain unclear.
Here, Nkx2.7 is demonstrated to compensate for Nkx2.5 loss of function and play a predominant role in the lateral development of the heart, including normal cardiac looping and chamber formation. Knocking down Nkx2.5 showed that heart development was normal from 24 to 72 hpf. However, when knocking down either Nkx2.7 or Nkx2.5 together with Nkx2.7, it appeared that the heart failed to undergo looping and showed defective chambers, although embryos developed normally before the early heart tube stage. Decreased ventricular myocardium proliferation and defective myocardial differentiation appeared to result from late-stage up-regulation of bmp4, versican, tbx5 and tbx20, which were all expressed normally in hearts at an early stage. We also found that tbx5 and tbx20 were modulated by Nkx2.7 through the heart maturation stage because an inducible overexpression of Nkx2.7 in the heart caused down-regulation of tbx5 and tbx20. Although heart defects were induced by overexpression of an injection of 150-pg Nkx2.5 or 5-pg Nkx2.7 mRNA, either Nkx2.5 or Nkx2.7 mRNA rescued the defects induced by Nkx2.7-morpholino(MO) and Nkx2.5-MO with Nkx2.7-MO.
Therefore, we conclude that redundant activities of Nkx2.5 and Nkx2.7 are required for cardiac morphogenesis, but that Nkx2.7 plays a more critical function, specifically indicated by the gain-of-function and loss-of- function experiments where Nkx2.7 is observed to regulate the expressions of tbx5 and tbx20 through the maturation stage.
PLoS ONE 02/2009; 4(1):e4249. · 4.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: ADP-ribosylation factor-like 6 (Arl6) mutation is linked to human disease and Arl6 interacts with Arl6 interacting protein (Arl6ip). However, the expression pattern and function of Arl6ip during embryogenesis are unknown. To confirm whether abnormal Arl6ip function might result in embryonic defects in zebrafish, we examined the expression patterns of arl6ip during embryogenesis, and they were maternally expressed and exhibited in the brain, optic primordia, hypochord, spinal cord, myotome, heart, fin-bud, kidney, trunk, and retina. Knockdown of Arl6ip revealed the following phenotypic defects: microphthalmia, disorganized pigment pattern, flat head, defective tectum, deficient pectoral fins, abnormal pneumatic duct, pericardial edema, and deformed trunk. Particularly, histological dissection of the retinae of arl6ip-morphants revealed that neuronal differentiation is severely delayed, resulting in no formation of retinal layers. We further confirmed that opsins of arl6ip-morphants were not transcribed. Based on this evidence, Arl6ip may play important roles in zebrafish ocular, heart, and fin-bud development.
Developmental Dynamics 01/2009; 238(1):232-40. · 2.54 Impact Factor
