鸡卵泡发育和退化过程中孕酮生成关键基因3β-HSD表达变化的调控研究

The follicle development, ovulation and regression are the most important processes in animal reproduction in females. After ovulation, mammalian follicles transformed to corpus luteum which the main function is the production of progesterone to establish pregnancy. Avian reproduction system is very different from mammals, such as the follicles don't form corpus luteum after ovulation, but the possible involvement of progesterone couldn't be ruled out. We have previously identified the differential expressed genes among the small-white follicles (SWF), largest follicles (F1) and post-ovulatory follicles (POF1) in chicken ovary by Solexa sequencing. Among the differentially expressed transcripts, genes encoding the three enzymes for progesterone synthesis were significantly up-regulated in the F1 follicles then decreased substantially in the POF1 follicles, indicate the regulation of progesterone synthesis in avian follicles are very different from mammals. In order to understand the molecular mechanisms control the progesterone synthesis before and after ovulation in avian follicles, we will study the regulation of 3-β-hydroxysteroid dehydrogenase, the most crucial enzyme for the progesterone synthesis, during follicular development and regression. The progesterone's function during avian follicle development and ovulation will also be examined to provide further guidance for its potential application for animal reproduction improvement.

摘要：研究卵泡周期性变化的分子调控意义重大。哺乳动物的排卵后卵泡形成黄体，主要功能是分泌孕酮。鸟类排卵后卵泡不形成黄体，但是否具有黄体样功能，一直存在争议。本课题组，前期以小白卵泡、F1卵泡、排卵后卵泡为材料进行了Solexa测序，发现合成孕酮的三个关键酶基因在F1卵泡表达量最高，而排卵后却急剧降低，充分说明禽类合成孕酮的方式跟哺乳动物截然不同。所以，本研究拟以合成孕酮的最关键酶基因3β-HSD为研究对象，深入分析排卵前后促进和抑制孕酮合成的分子调控机制，期望能更系统、全面的揭示孕酮在家禽卵泡发育中的作用，并可望为提高家禽产蛋性能的研究提供新的研究途径。

研究家禽卵泡发育分子调控机理可以帮助我们理解动物繁殖过程和提高农业生产效率。禽类排卵前卵泡孕酮合成达到最高，此与哺乳动物完全相反。本课题以鸡卵巢中一系列等级卵泡为材料，进行了高通量测序和筛选，发现合成孕酮的一系列关键酶基因在排卵前等级卵泡中表达量升高，而排卵后急剧降低。因此，本课题继续深入研究了三个关键酶基因（Star, Cyp11a1, Hsd3b）的表达规律和启动子甲基化的变化，进一步深入探明了Hsd3b排卵前后促进和抑制孕酮合成的分子调控机制。另外，针对测序筛选到的在卵泡发育和排卵中差异表达的MMPs和ANXA2基因家族，进行了基因功能研究，证明该基因调控的细胞外基质和血管生成在卵泡发育过程中的重要作用。本项目研究结果有助于我们更系统全面的揭示孕酮在家禽卵泡发育中的作用，并可望为提高家禽产蛋性能提供新的依据。