Zhu Guiyu, Mao Yong, Zhou Wendi, Jiang Yunliang
Department of Biology Science and Technology, Taishan University, Taian 271021, China.
Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Taian 271018, China.
PLoS One. 2015 Dec 30;10(12):e0146028. doi: 10.1371/journal.pone.0146028. eCollection 2015.
The molecular mechanisms associated with follicle maturation and ovulation are not well defined in avian species. In this study, we used RNA-seq to study the gene expression profiles of the chicken follicles from different developmental stages (pre-hierarchical, pre-ovulatory and post-ovulatory). Transcriptomic analysis revealed a total of 1,277 and 2,310 genes were differentially expressed when follicles progressed through the pre-hierarchical to hierarchical and pre-ovulatory to post-ovulatory transitions, respectively. The differentially expressed genes (DEG) were involved in signaling pathways such as adherens junction, apoptosis and steroid biosynthesis. We further investigated the transcriptional regulation of follicular steroidogenesis by examining the follicle-specific methylation profiles of Star (steroidogenic acute regulatory protein), Cyp11a1 (cytochrome P450, family 11, subfamily a, polypeptide 1) and Hsd3b (hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1), genes encoding the key enzymes for progesterone synthesis. The varied patterns of DNA methylation in proximal promoters of Star and Cyp11a1but not Hsd3b in different follicles could play a major role in controlling gene expression as well as follicular steroidogenic activity. Finally, the promoter-reporter analysis suggests that TGF-β could be involved in the regulation of Hsd3b expression during ovulation. Together, current data not only provide novel insights into the molecular mechanisms of follicular physiology in chicken follicles, but also present the first evidence of epigenetic regulation of ovarian steroidogenesis in avian species.
在鸟类中，与卵泡成熟和排卵相关的分子机制尚未完全明确。在本研究中，我们使用RNA测序技术研究了不同发育阶段（分级前、排卵前和排卵后）鸡卵泡的基因表达谱。转录组分析显示，当卵泡从分级前过渡到分级阶段以及从排卵前过渡到排卵后阶段时，分别共有1277个和2310个基因差异表达。差异表达基因（DEG）参与了诸如黏附连接、细胞凋亡和类固醇生物合成等信号通路。我们通过检测Star（类固醇生成急性调节蛋白）、Cyp11a1（细胞色素P450，家族11，亚家族a，多肽1）和Hsd3b（羟基-δ-5-类固醇脱氢酶，3β-和类固醇δ-异构酶1）的卵泡特异性甲基化谱，进一步研究了卵泡类固醇生成的转录调控，这些基因编码孕酮合成的关键酶。不同卵泡中Star和Cyp11a1而非Hsd3b近端启动子中不同的DNA甲基化模式可能在控制基因表达以及卵泡类固醇生成活性中起主要作用。最后，启动子-报告基因分析表明，TGF-β可能参与排卵期间Hsd3b表达的调控。总之，目前的数据不仅为鸡卵泡卵泡生理学的分子机制提供了新的见解，也为鸟类卵巢类固醇生成的表观遗传调控提供了首个证据。
