The dynamics of ciliogenesis in prepubertal mouse meiosis reveals new clues about testis maturation.

Primary cilia have recently been identified in mammalian spermatocytes, but their developmental regulation during testicular maturation remains poorly understood. Here, we investigate the dynamics of ciliogenesis during mouse puberty and show that primary cilia are not an intrinsic feature of spermatocytes during the first wave of meiosis, initiated at 8 days post partum (dpp). Ciliogenesis begins only at day 20 dpp, where cilia are detected across all stages of prophase I, indicating no direct association with synapsis or desynapsis. We further found that Aurora kinase A is associated with cilia disassembly in late diplotene and that spermatocytes retaining a polymerized cilium fail to assemble a bipolar spindle. In addition, proteomic analysis defined the 19-21 dpp period as a key developmental window associated with ciliogenesis and flagellogenesis. We also identified ciliated spermatocytes in the human testis, providing the first evidence of meiotic cilia in human meiocytes. This work reveals that ciliogenesis is a developmentally regulated process during testicular maturation in mouse.