Deficient spermiogenesis in mice lacking <i>Rlim</i>.

Abstract

The X-linked gene <i>Rlim</i> plays 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 systemic <i>Rlim</i> knockout (KO) die around implantation, male <i>Rlim</i> KO mice appear healthy and are fertile. Here, we report an important role for <i>Rlim</i> in testis where it is highly expressed in post-meiotic round spermatids as well as in Sertoli cells. Systemic deletion of the <i>Rlim</i> gene results in lower numbers of mature sperm that contains excess cytoplasm, leading to decreased sperm motility and in vitro fertilization rates. Targeting the conditional <i>Rlim</i> cKO specifically to the spermatogenic cell lineage largely recapitulates this phenotype. These results reveal functions of <i>Rlim</i> in male reproduction specifically in round spermatids during spermiogenesis.