Transcriptomic analysis of different stages of pigeon ovaries by RNA-sequencing

The pigeon ovary is an ideal model for deciphering the molecular mechanism of folliculogenesis. While most analysis has focused on the influence of hormones and factors on ovarian follicle development in this model, changes occurring in the ovarian stroma can also be extremely informative. Here, we profiled the transcriptome of pigeon ovaries at pre-ovulation, post-ovulation, and 5-6 days after ovulation using RNA-sequencing to gain insights into the molecular and cellular events mediating ovary activity. We obtained 44,784,505 clean reads that aligned with 14,088 genes. Gene expression profile analysis identified 409 differentially expressed genes between pre- and post-ovulation; 96 genes were up-regulated genes while 313 genes were down-regulated. Gene ontology analysis of the down-regulated genes revealed significant enrichment in components of the immune response, immune system, antigen processing and presentation, receptor binding, and biological adhesion. Pathway analyses of the high-expression genes of the post-ovulation ovary identified enrichment in phagosomes, lysosomes, cytokine-cytokine receptor interactions, cell adhesion molecules, and the Toll-like receptor signaling. These data together suggest that post-ovulatory follicle regression and elimination occurs through an immune response. Mol. Reprod. Dev. 83: 640-648, 2016. © 2016 Wiley Periodicals, Inc.