Transcriptome-wide Dynamics of m6A mRNA Methylation During Porcine Spermatogenesis.

Spermatogenesis is a continual process that occurs in the testes, in which diploid spermatogonial stem cells (SSCs) differentiate and generate haploid spermatozoa. This highly efficient and intricate process is orchestrated at multiple levels. N6-methyladenosine (m6A), an epigenetic modification prevalent in mRNAs, is implicated in transcriptional regulation during spermatogenesis. However, the dynamics of m6A modification in non-rodent mammalian species remains unclear. Here we systematically investigated the profile and role of m6A during spermatogenesis in pigs. By analyzing the transcriptomic distribution of m6A in spermatogonia, spermatocytes, and round spermatids, we identified a globally conserved m6A pattern between porcine and murine genes with spermatogenic function. We found that m6A was enriched in a group of genes that specifically encode the metabolic enzymes and regulators. In addition, transcriptomes in porcine male germ cells could be subjected to the m6A modification. Our data showed that m6A played the regulatory roles during spermatogenesis in pigs, which is similar to that in mice. Illustrations of this point were three genes (SETDB1, FOXO1, and FOXO3) that were crucial to the determination of the fate of SSCs. To the best of our knowledge, this study has for the first time uncovered the expression profile and role of m6A during spermatogenesis in large animals and contributes to insights into the intricate transcriptional regulation underlying the lifelong male fertility in non-rodent mammalian species.