Transcription and post-transcriptional regulation of spermatogenesis

Abstract

Spermatogenesis in mammals is achieved by multiple players that pursue a common goal of generating mature spermatozoa. The developmental processes acting on male germ cells that culminate in the production of the functional spermatozoa are regulated at both the transcription and post-transcriptional levels. This review addresses recent progress towards understanding such regulatory mechanisms and identifies future challenges to be addressed in this field. We focus on transcription factors, chromatin-associated factors and RNA-binding proteins necessary for spermatogenesis and/or sperm maturation. Understanding the molecular mechanisms that govern spermatogenesis has enormous implications for new contraceptive approaches and treatments for infertility.

Figure 1.

(a) Schematic representation of developing germ cells imbedded in a Sertoli cell in the seminiferous tubule. Spermatogonia undergo mitotic divisions, ultimately giving rise to meiotic spermatocytes. Meiosis causes reductive divisions, leading to the generation of haploid round spermatids. These latter cells undergo a series of differentiation events to become elongated spermatids, which detach from the Sertoli cell and travel down the seminiferous tubule lumen to reach the epididymis (not shown). (b) Recently defined Sertoli-cell-expressed transcription factors that guide the survival and differentiation of the adjacent germ cells.

Figure 2.

Germ-cell regulatory factors crucial for spermatogenesis. Shown are germ-cell-expressed transcription factors, chromatin-associated factors, and RNA-binding proteins that have recently been shown to have roles in spermatogenesis. Horizontal bars indicate the approximate germ-cell stage(s) at which these factors are expressed. Shaded areas within the horizontal bars indicate the approximate germ-cell stage(s) at which these factors act. Note that factors that act in the Sertoli cell are not shown here but instead are in figure 1b. Also not shown is FOXI1, which promotes sperm maturation in the epididymis.