Conclusion
Our data demonstrate that YTHDF2 facilitates the timely turnover of phase-specific transcripts to ensure the proper progression of spermatogenesis, which highlights a critical role of YTHDF2 in spermatogenesis.
Methods
Ythdf2 germ cell conditional knockout mice were obtained by crossing Ythdf2-floxed mice with Vasa-Cre and Stra8-Cre mice. Haematoxylin and eosin (HE) staining, immunofluorescent staining and Western blotting were used for phenotyping. CASA, IVF and ICSI were applied for sperm function analysis. RNA-seq, YTHDF2-RIP-seq and quantitative real-time PCR were used to explore transcriptome changes and molecular mechanism analysis.
Results
Our results showed that YTHDF2 was highly expressed in spermatogenic cells. The germ cell conditional knockout males were sterile, and their sperm displayed malformation, impaired motility, and lost fertilization ability. During differentiated spermatogonia transiting to pachytene spermatocyte, most m6 A-modified YTHDF2 targets that were degraded in control germ cells persisted in pachytene spermatocytes of Ythdf2-vKO mice. These delayed mRNAs were mainly enriched in pathways related to the regulation of transcription, and disturbed the transcriptome of round spermatid and elongated spermatid subsequently.