Profiles and roles of N6-methyladenosine modification in bovine oocyte maturation

BACKGROUND: Bovine oocyte quality is crucial for successful in vitro embryo production; therefore, elucidating the mechanisms underlying oocyte maturation is essential. N6-methyladenosine (m6A) modification plays a pivotal role in gametogenesis and embryonic development. However, the dynamic landscape and functional significance of m6A modification during bovine oocyte maturation remain poorly understood. RESULTS: We performed transcriptome-wide m6A profiling analysis on bovine oocytes at the GV and MII stages using MeRIP-seq and RNA-seq. A total of 6323 differential m6A peaks were identified between the two groups, with 4422 significantly upregulated and 1901 significantly downregulated. The combined analysis of MeRIP-seq and RNA-seq identified 262 genes with significant differences in both methylation modification and transcriptome levels. GO and KEGG enrichment analyses of these genes indicated that they were significantly enriched in biological processes and signaling pathways, including endocytosis, thermogenesis, ribosome biogenesis, cellular metabolism, the Apelin signaling pathway, and the HIF-1 signaling pathway. Finally, we assessed the roles of m6A modification in bovine oocyte maturation. The results demonstrated that inhibition of m6A modification impairs both nuclear and cytoplasmic maturation of bovine oocytes. CONCLUSIONS: Our results provide a comprehensive m6A modification profile during bovine oocyte maturation. Moreover, we found that inhibition of m6A modification results in meiotic arrest and impaired oocyte maturation. These findings offer a theoretical foundation for further studies on the function of RNA modifications in oocyte maturation.