Table5_Comparative Analysis Among Different Species Reveals That the Androgen Receptor Regulates Chicken Follicle Selection Through Species-Specific Genes Related to Follicle Development.XLSX

The differences in reproductive processes at the molecular level between viviparous and oviparous animals are evident, and the site in the ovary that synthesizes sex hormones (androgens and oestrogens) and the trends for enriching sex hormones during follicle development in chickens are different from those in mammals, suggesting that the effect of sex hormones on follicle development in chickens is probably different from that in viviparous animals. To explore the specific role of androgen receptors (ARs) on chicken follicular development, we matched the correspondence of follicular development stages among chickens, humans, cows and identified chicken-specific genes related to follicle development (GAL-SPGs) by comparing follicle development-related genes and their biological functions among species (chickens, humans, and cows). A comparison of the core transcription factor regulatory network of granulosa cells (or ovaries) based on super-enhancers among species (chicken, human, and mouse) revealed that AR is a core transcriptional regulator specific to chickens. In vivo experiments showed that inhibition of AR significantly reduced the number of syf (selected stage follicles) in chickens and decreased the expression of GAL-SPGs in F5 follicles, while in vitro experiments showed that inhibition of AR expression in chicken granulosa cells (GCs) significantly down-regulated the expression levels of GAL-SPGs, indicating that AR could regulate follicle selection through chicken-specific genes related to follicle development. A comparison among species (77 vertebrates) of the conserved genomic regions, where chicken super-enhancers are located, revealed that the chicken AR super-enhancer region is conserved in birds, suggesting that the role of AR in follicle selection maybe widespread in birds. In summary, we found that AR can regulate follicle selection through chicken-specific genes related to follicle development, which also emphasizes the important role of AR in follicle selection in chickens and provides a new perspective for understanding the unique process of follicle development in chickens. Our study will contribute to the application of androgens to the control of egg production in chickens and suggests that researchers can delve into the mechanisms of follicle development in birds based on androgen/androgen receptors.

胎生动物与卵生动物的生殖过程在分子层面存在显著差异。鸡卵巢中合成性激素：雄激素（androgens）、雌激素（oestrogens）的位点，以及卵泡发育过程中性激素富集的趋势，均与哺乳动物存在显著区别，提示性激素对鸡卵泡发育的调控作用可能有别于胎生动物。
为探究雄激素受体（androgen receptors, ARs）在鸡卵泡发育中的具体功能，本研究匹配了鸡、人、牛三个物种的卵泡发育阶段对应关系，并通过跨物种（鸡、人、牛）比较卵泡发育相关基因及其生物学功能，筛选得到鸡特异性卵泡发育相关基因（GAL-SPGs）。
通过对鸡、人、小鼠三个物种基于超级增强子（super-enhancers）的颗粒细胞（granulosa cells，或卵巢）核心转录因子调控网络进行比较分析，发现AR是鸡特异性的核心转录调控因子。
体内实验结果显示，抑制AR可显著降低鸡的选择期卵泡（selected stage follicles, syf）数量，并下调F5卵泡中GAL-SPGs的表达水平；体外实验则表明，在鸡颗粒细胞（granulosa cells, GCs）中抑制AR表达，可显著下调GAL-SPGs的表达量，这表明AR可通过鸡特异性卵泡发育相关基因调控卵泡选择。
通过对77种脊椎动物的鸡超级增强子所在保守基因组区域进行跨物种比较，发现鸡AR超级增强子区域在鸟类中具有保守性，提示AR在卵泡选择中的作用可能广泛存在于鸟类类群中。
综上，本研究发现AR可通过鸡卵泡发育相关特异性基因调控卵泡选择，这既明确了AR在鸡卵泡选择过程中的关键作用，也为解析鸡卵泡发育的独特机制提供了全新视角。本研究将为雄激素类物质应用于鸡产蛋性能调控提供理论支撑，同时提示研究者可基于雄激素/雄激素受体深入探究鸟类卵泡发育的调控机制。