Protein synthesis during mouse spermatogenesis.

Spermatogenesis is composed of three consecutive stages, mitosis, meiosis and spermiogenesis, during which spermatogenic cells undergo continuous molecular and cellular transformation. Regulation of gene expression has been underlying major molecular mechanisms that govern the progressive cell fate determination during spermatogenesis. Besides epigenetic and transcriptional controls, the un-coupled transcription and translation is a common phenomenon conserved across phyla during spermatogenesis. Translational regulation determines the dynamic proteomic landscapes in spermatogenic cells. Aberrant protein synthesis caused by mutations in RNA binding proteins (RBPs) and translation regulators often cast detrimental effects on spermatogenesis in a stage-specific manner, leading to male infertility. Regulation of gene expression at the post-transcriptional and translational levels bear advantages of fast and flexible responses to changing environment, coordination of cellular states including energy and nutrient availability, preservation of genomic fidelity and quantitative and qualitative control of proteins, the functional units of the cell. How cell type-specific translation is regulated during spermatogenesis is largely unclear. In this review, we will first introduce general features of protein synthesis and what have been revealed during mouse spermatogenesis when aberrant protein synthesis occurred. We will then analyze the differential signaling pathways and intracellular factors that cooperatively regulate proteomic landscapes in spermatogenic cells at various stages of spermatogenesis. Protein synthesis is a fundamental mechanism underlying cell fate determination. Taking advantage of current advancements in methodology, future research in this area will unveil the design principles that govern how cells program and maintain functional proteome during development and disease.