Centriole Duplication, Maturation, and Transformation During Mammalian Spermatogenesis

Spermatogenesis is the process by which spermatozoa are produced from spermatogonia through two rounds of meiotic divisions to form spermatocytes, followed by a series of transformations to form spermatids. Unlike what occurs in oogenesis, during which centrioles are eliminated, centrioles are retained throughout meiosis in spermatocytes and are inherited by spermatids, where they function as basal bodies for the formation of flagella. In spermatocytes, centrioles are duplicated twice independently of pre-meiotic DNA synthesis. In spermatids, centrioles attach to the nucleus and undergo a unique remodeling process. These features are not observed in somatic cells, and the mechanisms that regulate these specialized events are still largely unknown. In this review, we provide an up-to-date overview of the roles of centrioles and the molecular mechanisms that support their functions in spermatogonia maintenance, meiosis in spermatocytes, spermatid transformation into spermatozoa, and the first zygotic division after fertilization.