Comparative analysis among different species reveals that androgen receptor is a core transcriptional factor regulating the chicken follicular selection and ovulation [ChIP-Seq]

The differences of reproductive processes at molecular levels between the viviparous and oviparous animals are still unclear, and in the oviparous animal, the locations to synthetize sex hormones and also the trends to enrich sex hormones during follicle development are different from that of viviparous animals. To explore the commonalities (key factors for follicular development) and individualities (factors that cause differences among species) in the follicular development of viviparous and oviparous animals, we compared the similarities and differences in follicle development between viviparous and oviparous animals in terms of transcriptome and super-enhancer-based transcriptional regulation, using humans, bovines, and mice as representatives of viviparous animals and chickens, for oviparous animals. It was found that follicle development in molecular terms tended to be more conservative between viviparous and oviparous animals. Estrogen receptors and androgen receptors occupied central positions in the transcriptional regulatory networks of viviparous and oviparous animals respectively, which may be related with differences in the synthesis and secretion of sex hormones between oviparous and viviparous animals. The role of androgen receptors in chicken follicle development was verified through cell level and field experiments. Our study would facilitate to extend existing results of follicle development in viviparous animals to oviparous animals, and our results emphasized the importance of the androgen receptor in chicken follicle development. Comparative analysis among different species in follicle development will help us to gain insight on the mechanisms of follicle development. Examination of histone modification H3K27ac (Abcam, ab4729) in granulosa cells in prehierarchical and preovulatory follicles of chickens.