Comprehensive Analysis of mRNAs and miRNAs in the Ovarian Follicles of Uniparous and Multiple Goats at Estrus Phase

Abstract Background Fertility is an important economic trait in production of meat goat, and follicular development plays an important role in fertility. Despite many mRNAs and microRNAs (miRNAs) have been found in playing critical roles in ovarian biological processes, the interactions between mRNAs and miRNAs in follicular development is not yet completely understood. In addition, less attention has been given to the single follicle (dominant or atretic follicle) in goat. The study was aimed to identify mRNAs, miRNAs and signaling pathways as well as their interaction networks in the ovarian follicles (large follicles and small follicles) of multiple and uniparous goats (Chuanzhong Black Goats) at estrus phase by using a deep RNA-sequencing (RNA-seq) method.Results The result showed that there were more large follicles in multiple than in uniparous goats ( P 0.05). For the small follicles of multiple and uniparous goats at estrus phase, 289 differentially expressed mRNAs (DEmRNAs) and 16 DEmiRNAs were identified; and for the large follicles, 195 DEmRNAs and 7 DEmiRNAs were identified. Ovarian steroidogenesis and steroid hormone biosynthesis were significantly enriched in small follicles, while ABC transporters and steroid hormone biosynthesis in large follicles. The results of qRT-PCR were generally consistent with the RNA-seq data. The mRNA-miRNA interaction network showed that CD36 (miR-122, miR-200a, miR-141), TNFAIP6 (miR-141, miR-200a, miR-182), CYP11A1 (miR-122), SERPINA5 (miR-1, miR-206, miR-133a-3p, miR-133b) and PTGFR (miR-182, miR-122) might be related to fertility, but need further verification.Conclusion This study provides the first identification of the DEmRNAs and DEmiRNAs as well as their interactions in the follicles of multiple and uniparous goats at estrus phase by using RNA-seq technology. These analyses provide new clues to uncover molecular mechanisms and signaling networks of goat reproduction which could be potentially used to increase ovulation rate and kidding rate in goat.