Transcriptome analysis of granulosa cell layer of hierarchical follicles during the egg-laying interval in pigeons.

1. Follicular development involves a series of critical processes, including the recruitment and selection of follicles, regulated by complex mechanisms. However, the specific genes and molecular mechanisms involved in follicular development in pigeons during the egg-laying interval (LI) are still unknown.2. To identify key genes that regulate follicular development in pigeons, the largest follicles (F1) and the second-largest follicles (F2) were collected on the third (LI3), fifth (LI5) and seventh (LI7) days of the LI for RNA sequencing and bioinformatics analyses.3. In F1 follicle granulosa cells (F1GC), 7,743 and 2,791 differentially expressed genes (DEG) were identified in the LI3 vs. LI5 group and the LI5 vs. LI7 group, respectively. In F2 follicle granulosa cells (F2GC), 3,072 DEG were detected in the LI5 vs. LI7 group.4. Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) analyses were performed and a protein-protein network for the DEG was constructed. This allowed the identification of hub genes (FKBP4, RAF1, CTNNB1, ENO1, FST and PHB) associated with hierarchical follicular development in pigeons.