ABSTRACT: Ovarian aging results in follicular failure and atresia, leading to a decline in both the quantity and quality of oocytes. N6-methyladenosine (m6A) has been demonstrated to play a regulatory role in the reproductive functions of female animals; however, the regulatory mechanisms of m6A in the ovaries of sheep remain unclear. In the present study, ovarian tissues from 1~2 year-old and 5~6 year-old Cele black sheep were collected and analyzed using MeRIP-seq and RNA-seq sequencing. A total of 109 differentially methylated genes were identified, including 7 genes that were up-regulated in both methylation and mRNA expression, 55 genes that were up-regulated in methylation while down-regulated in mRNA expression, and 33 genes that were down-regulated in both methylation and mRNA expression. Additionally, 14 genes exhibited down-regulation in methylation and up-regulation in mRNA expression. Differential methylation peaks (DMPs) were found to be significantly enriched in the BMP signaling pathway, uterine embryonic development, histone acetyltransferase activity, and VEGF signaling pathway by GO and KEGG enrichment analysis. Differentially expressed genes (DEGs) were significantly enriched in negative regulation of the I-kappaB kinase/NF-kappaB signalling pathway, positive regulation of leukocyte adhesion to vascular endothelial cells, histone methyltransferase binding, transcriptional co-repressor activity, and cellular senescence. The results suggest that differentially expressed genes may influence various biological functions, including transcription, translation, aging, development, regeneration, and immune responses in the ovary of sheep. In this study, we constructed the first comprehensive whole transcriptome analysis map of the sheep ovary, which provides a theoretical foundation for investigating the transcriptional regulation mechanisms of m6A modification in the ovary.
