Testicular stage- and cell-specific expression of F-actin binding proteins.

Abstract

Sertoli cells are essential to successful, continuous sperm production and are responsible for many processes throughout spermatogenesis including germ cell movement and compartmentalization of the seminiferous tubule interior. These functions are able to be performed by the Sertoli cells due to the F-actin cytoskeleton present within the seminiferous tubules that facilitates cell movement and adhesion. While some molecular players that regulate the testicular F-actin cytoskeleton are known, the expression of other actin-related genes in the mammalian testis remains unknown. In this study, we have revisited previously published next generation sequencing data and combined this with immunohistochemical analysis to identify the cell- and stage-specific expression of multiple Alpha-actinin (α-actinin) and myosin genes, and protein products. This work provides the first characterization of α-actinin and myosin localization within murine testes throughout spermatogenesis. We have identified α-actinin 3 (ACTN3), α-actinin 4 (ACTN4), myosin VIIa (MYO7A), and myosin 10 (MYO10) as potential functional candidates regulating cytoskeleton dynamics throughout spermatogenesis based on the high mRNA expression observed of these genes within Sertoli cells, as well as the specific protein localization observed within Sertoli cells. We additionally found expression MYO7A within early spermatogonia and meiotic germ cells, suggesting a potential role of these proteins during mitotic and meiotic division. Overall, this study provides insight to the expression of many F-actin related genes during the mammalian testicular maturation and contributes to our understanding of dynamic Sertoli cell gene expression in mammalian testes.