Transcriptomic and proteomic analyses between small yellow follicles and the smallest hierarchical follicles reveal a role of VLDLR in chicken follicle selection

Abstract

Background Follicle selection in chicken refers to the process of selecting one from a group of small yellow follicles (SY, 6-8mm in diameter) to enter the 12-15 mm hierarchical follicles (usually F6 follicles), which is a an important process affecting laying performance in the poultry industry. Although transcripromic analysis on chicken ovarian follicles was reported, integrated analysis on chicken follicles around selection by using both transcripromic and proteomic approaches was still lacking. In this study, we compared the proteomes and transcriptomes of SY and F6 follicles of laying hens and found some genes involved in chicken follicle selection.Results Transcriptomic analysis revealed 855 differentially expressed genes (DEGs) between SY follicles and F6 follicles of laying hens, among which 202 were upregulated and 653 were downregulated. Proteomic analysis revealed 259 differentially expressed proteins (DEPs), including 175 upregulated and 84 downregulated proteins. Among the identified DEGs and DEPs, the expression changes of seven genes including VLDLR1,WIF1, NGFR, AMH, BMP15, GDF6 and MMP13 , and nine proteins including VLDLR, VTG1, VTG3, PSCA, APOB, APOV1, F10, ZP2 and ZP3L2 were validated. In addition VLDLR expression was significantly down-regulated in F6 follicles compared with SY follicles, was signifcantly higher in the GCs than in the TCs and was stimulated by FSH in GCs of both hierarchical and prehierarchical follicles.Conclusions By comparing the proteomes and transcriptomes of SY follicles and F6 of laying hens, we identified some differentially expressed proteins/genes that might play certain roles in chicken follicle selection. These data may contribute to identification of the functional genes and proteins involved in chicken follicular development and selection.