Deficient spermiogenesis in mice lacking Rlim

Abstract

The X-linked geneRlimplays major roles in female mouse development and reproduction, where it is crucial for the maintenance of imprinted X chromosome inactivation in extraembryonic tissues of embryos. However, while females carrying a systemicRlimknockout (KO) die around implantation, maleRlimKO mice appear healthy and are fertile. Here, we report an important role forRlimin testis where it is highly expressed in post-meiotic round spermatids as well as in Sertoli cells. Systemic deletion of theRlimgene results in lower numbers of mature sperm that contains excess cytoplasm, leading to decreased sperm motility and in vitro fertilization rates. Targeting the conditionalRlimcKO specifically to the spermatogenic cell lineage largely recapitulates this phenotype. These results reveal functions ofRlimin male reproduction specifically in round spermatids during spermiogenesis.