鸡卵巢卵泡发育受复杂而动态的基因表达调控。核受体5A1和5A2(分别为NR5A1和NR5A2)是调节哺乳动物类固醇激素产生和性腺发育的关键基因;然而,关于鸡卵巢卵泡发育的研究很少。在这项研究中,我们研究了NR5A1和NR5A2对鸡卵泡发育的功能。成果显示NR5A1和NR5A2在小黄色卵泡和F5中表达显著增高。此外,NR5A1和NR5A2在产卵高峰母鸡(30周)卵泡组织中的表达明显高于产卵后期母鸡(60周)的卵泡组织,在颗粒细胞(GC)中具有高表达丰度。NR5A1和NR5A2的过表达显著促进培养的GC的增殖和抑制凋亡;上调STAR,来自排卵前卵泡(po-GC)的GC中CYP11A1和CYP19A1的表达以及雌二醇(E2)和孕酮(P4)的合成;以及增加的STAR,CYP11A1和CYP19A1启动子活性。此外,促卵泡激素处理显著上调po-GC中NR5A1和NR5A2的表达,显著促进FSHR,CYP11A1和HSD3B1在来自分级前卵泡和po-GC的GC中的表达。NR5A1的核心启动子区域在翻译起始位点(1)的-1,095-至-483-bp和-2,054-至-1,536-bp区域被鉴定,NR5A2的核心启动子区位于-998至-489bp。在NR5A1基因的核心启动子区鉴定出两个单核苷酸多态性(SNP),高产量和低产量的鸡肉群体之间存在差异。我们的研究表明,NR5A1和NR5A2通过促进GC增殖和E2和P4激素合成以及抑制细胞凋亡来促进鸡卵泡发育。此外,我们确定了调控NR5A1和NR5A2表达的启动子核心区或功能位点。
Chicken ovarian follicle development is regulated by complex and dynamic gene expression. Nuclear receptor 5A1 and 5A2 (
NR5A1 and NR5A2, respectively) are key genes that regulate steroid hormone production and gonadal development in mammals; however, studies on follicular development in the chicken ovary are scarce. In this study, we investigated the functions of
NR5A1 and NR5A2 on follicle development in chickens. The results showed that the expression of
NR5A1 and NR5A2 was significantly higher in small yellow follicles and F5. Furthermore, the expression of NR5A1 and NR5A2 was significantly higher in follicular tissues of peak-laying hens (30 wk) than in follicular tissues of late-laying hens (60 wk), with high expression abundance in granulosa cells (GC). The overexpression of
NR5A1 and NR5A2 significantly promoted proliferation and inhibited apoptosis of cultured GC; upregulated STAR, CYP11A1, and CYP19A1 expression and estradiol (E2) and progesterone (P4) synthesis in GC from preovulatory follicles (po-GC); and increased STAR, CYP11A1, and CYP19A1 promoter activities. In addition, follicle-stimulating hormone treatment significantly upregulated
NR5A1 and NR5A2 expression in po-GC and significantly promoted FSHR, CYP11A1, and HSD3B1 expression in GC from pre-hierarchical follicles and po-GC. The core promoter region of NR5A1 was identified at the -1,095- to -483-bp and -2,054- to -1,536-bp regions from the translation start site (+1), and the core promoter region of NR5A2 was at -998 to -489 bp. Two single nucleotide polymorphisms (SNP) were identified in the core promoter region of the NR5A1 gene, which differed between high- and low-yielding chicken groups. Our study suggested that NR5A1 and NR5A2 promoted chicken follicle development by promoting GC proliferation and E2 and P4 hormone synthesis and inhibiting apoptosis. Moreover, we identified the promoter core region or functional site that regulates NR5A1 and NR5A2 expression.