SRSF10 is essential for progenitor spermatogonia expansion by regulating alternative splicing

Alternative splicing expands the proteome complexity and plays essential roles in tissue development and human diseases. However, how spermatogenesis is regulated by alternative splicing remains largely unknown. Here, using germ cell-specific knockout mouse model, we demonstrate that the splicing factor Srsf10 is essential for spermatogenesis and male fertility. Depletion of Srsf10 in germ cells had little effect on the formation of SSCs but impeded the expansion of progenitor spermatogonia, leading to the failure of spermatogonia differentiation and meiosis initiation. This was evidenced by the decreased expression of progenitor cell markers in bulk RNA-seq, and much less progenitor and differentiating spermatogonia in single-cell RNA-seq data. Furthermore, the expression of genes involved in cell cycle was abnormal in all subtypes of spermatogonia identified in single-cell RNA-seq data. Notably, using isolated spermatogonia, we found that Srsf10 depletion disturbed the alternative splicing of hundreds of genes, which were preferentially associated with cell cycle, mitotic cell cycle checkpoint and germ cell development, including Dazl, Kit, Ret, Sycp1, Nasp and Bora. These data suggest that SRSF10 is critical for the expansion of progenitor spermatogonia by regulating alternative splicing, expanding our understanding of the novel mechanism underlying spermatogenesis. Overall design: Transcriptional profiles of P3, P6 and P8 testes from Control and Srsf10-cKO mice; Transcriptional profiles of isolated THY1+ cells from Control and Srsf10-cKO mice at P6; Single-cell RNA seq profiles of isolated spermatogonia (THY1+ or Kit+) from Control and Srsf10-cKO mice at P8; PacBio Isoform Sequencing (Iso-seq) profiles of isolated THY1+ cells from Control and Srsf10-cKO mice at P6 LACE-seq of isolated THY1+ cells from Control and Srsf10-cKO mice at P6