Perez-Martin, S. | Search bioRxiv

bioRxiv2025

The dynamics of ciliogenesis in prepubertal mouse meiosis reveal new clues about testicular maturation during puberty

The primary cilium, a solitary and non-motile extension of the plasma membrane, has recently been identified in adult male mouse spermatocytes. However, very little is known about when these cilia emerge during testicular maturation and what their function is. In the context of fertility establishment during puberty, this study investigates the dynamics of ciliogenesis in prepubertal mouse spermatocytes. Our findings reveal that primary cilia are not an intrinsic feature of spermatocytes during the first wave of meiosis, which initiates at 8 days post-partum (dpp). Instead, cilia begin polymerizing at 20 dpp, after first meiotic wave has been completed, and are present in spermatocytes across all stages of prophase I. Thus, no direct correlation between cilia polymerization and the initiation of synapsis or desynapsis was found, although chemical ablation of cilia may delay DNA repair during prophase I. Typical adult cilia features, which are shorter and restricted to zygotene spermatocytes, are settled upon acquisition of sexual maturity. This study also highlights that the emergence of ciliated spermatocytes in prepuberal mice coincides with the onset of flagellogenesis, hinting at a potential link between the regulation of the formation of both types of axonemes within the tissue developing environment. Proteomic analyses further identify temporal regulators of axoneme assembly, providing valuable targets for future research to unravel the molecular pathways underlying ciliogenesis, flagellogenesis, and their roles in spermatogenesis. We explored distinct regulatory mechanisms of ciliogenesis during the first meiotic wave and found that Aurora kinase A (AURKA) is a critical regulator of cilia disassembly during late diplotene, with evidence suggesting that centrosome migration and cilia depolymerization are mutually exclusive events during meiosis. In summary, this study provides the first detailed characterization of primary cilia dynamics during early testicular maturation in mice, revealing their spatiotemporal regulation, candidate molecular mediators, and potential roles during meiosis. These findings lay the groundwork for understanding the physiological relevance of meiotic cilia in spermatogenesis and testicular development.

cell biology↗

bioRxiv2022

The male mouse meiotic cilium emanates from the mother centriole at zygotene prior to centrosome duplication

Cilia are hair-like projections of the plasma membrane with an inner microtubule skeleton known as axoneme. Motile cilia and flagella beat to displace extracellular fluids, playing important roles in the airways and reproductive system, among others. Instead, primary cilia function as cell type-dependent sensory organelles, detecting chemical, mechanical or optical signals from the extracellular environment. Cilia dysfunction is associated with genetic diseases called ciliopathies, and with some types of cancer. Cilia have been recently identified in zebrafish gametogenesis as an important regulator of the bouquet conformation and recombination. However, there is very little information about the structure and functions of cilia in mammalian meiosis. Here we describe the presence of cilia in male mouse meiotic cells. These solitary cilia form transiently in 20% of zygotene spermatocytes and reach considerable lengths (up to 15 m). CEP164 and CETN3 localization studies indicate that these cilia emanate from the mother centriole, prior to centrosome duplication. In addition, the study of telomeric TFR2 suggests that these cilia are not directly related to the bouquet conformation during early male mouse meiosis. Instead, based on TEX14 labeling of intercellular bridges in spermatocyte cysts, we suggest that mouse meiotic cilia may have sensory roles affecting cyst function during prophase I.

cell biology↗