Role of CEP112 and hnRNPA2B1 complex phase separation in RNA granule translation during spermiogenesis in humans and mice

Here, we report that knocking out Cep112 in mice causes male infertility with various sperm abnormalities and phenotypes consistent with human asthenoteratozoospermia. Microscopic observations revealed CEP112 is a novel component of atypical centrioles in human sperm cells. Mechanically, as an intrinsically disordered region rich RNA binding protein, CEP112 interacted with hnRNPA2B1 and condensed with key spermiogenesis-related mRNA molecules (Fsip2, Cfap61, and Cfap74) via liquid liquid phase separation, which promoted RNA transport and the maintenance of local translation during spermiogenesis. Furthermore, two patients with bi-allelic variants in CEP112 were identified in a cohort of 568 unrelated infertile men, and in vitro experiments showed the mutations affected the phase-separation characteristics. Our findings provide new information on the roles of CEP112 and LLPS in male reproductive biology.