Loss of cilia drives centriole clustering and elimination during mammalian spermatogenesis

Abstract

Cilia are microtubule-based organelles essential for signaling and motility, and their dysfunction causes ciliopathies often associated with infertility. In male germ cells, two types of cilia are present: zygotene primary cilia and sperm flagella. To define the role of cilia in spermatogenesis, we conditionally ablated the distal appendage protein CEP164, required for basal body docking and ciliogenesis, in male germ cells. CEP164 localized to the mother centriole/basal body throughout spermatogenesis, and its loss led to male infertility accompanied by absence of both zygotene cilia and sperm flagella. Despite defective ciliogenesis, meiotic chromosome pairing and DNA double-strand break repair proceeded normally. However, round spermatids exhibited basal body docking and flagellogenesis defects, and frequently formed supernumerary centriole clusters that were subsequently eliminated via residual bodies. Live-cell imaging revealed that centrioles were highly mobile, and centriole pairs from neighboring cells often associated through intercellular bridges, forming aggregates. These results establish that basal body docking is crucial for retaining centrioles within spermatids, and its disruption leads to centriole clustering and loss. In contrast, zygotene cilia are dispensable for meiotic chromosome pairing and DNA repair during mammalian spermatogenesis.