YTHDF2 is essential for spermatogenesis and fertility by mediating a wave of transcriptional transition in spermatogenic cells

Acta Biochim Biophys Sin (Shanghai). 2021 Oct 19;gmab148. doi: 10.1093/abbs/gmab148. Online ahead of print.

Abstract

The dynamic and reversible regulation roles of m6A modification and the characterization of m6A readers have provided new insights into spermatogenesis at the post-transcriptional level. YTHDF2, as an m6A reader, has been reported to mediate the m6A-containing transcript decay during the mouse oocyte maturation, embryonic stem cell differentiation, neural development, and zebrafish maternal-to-zygotic transition. However, the roles of YTHDF2 in mammalian spermatogenesis are uncertain. Here, we generated germ cell-specific Ythdf2 mutants (Ythdf2-vKO) at a C57BL/6J background and demonstrated that YTHDF2 is essential for mouse spermatogenesis and fertility. Ythdf2-vKO provides oligoasthenoteratozoospermia phenotype with increased apoptosis in germ cells. High-throughput RNA-seq analysis showed that a group of mRNAs is upregulated in Ythdf2-vKO mouse testis; further analysis and MeRIP-qPCR data showed that most of the upregulated genes in Ythdf2-vKO mouse testis are modified with m6A and are YTHDF2 candidate binding genes. Interestingly, RNA-seq analysis combined with our previous single-cell transcriptomics data of mouse spermatogenesis pointed out the failure of a wave of transcript transition during the spermatogenesis of Ythdf2-vKO mice, which was confirmed by gene expression analysis using qPCR of diplotene spermatocytes and round spermatids obtained through fluorescence-activated cell sorting. Our study demonstrates the fundamental role of YTHDF2 during mouse spermatogenesis and provides a potential candidate for the diagnosis of male infertility with the oligoasthenoteratozoospermia syndrome.

Keywords: YTHDF2 protein; infertility; m6A; oligospermia; spermatogenesis.