Differential Expression of Genes Involved in Early Events of Spermatogenesis in Mice

Spermatogenesis is a complex and well-orchestrated process, in which Spermatogonial Stem Cells (SSCs) divide and differentiate to produce unlimited numbers of mature spermatozoa. This process is continuous throughout the adult life in most mammals. The seminiferous epithelium consists of only one somatic cell type, sertoli cell [1] and many different germ cell types [2]. Sertoli cells play a nurturing role in coordinating and supporting important events of spermatogenesis which occurs in mitotic, meiotic and post meiotic phases. Spermatogenesis is initiated by the division of stem cells (primitive type A spermatogonia) to form type B spermatogonia. These differentiated spermatogonial cells enter a meiotic prophase as preleptotene spermatocytes. The spermatocytes continue to mature as they go through the leptotene, zygotene and pachytene phases of meiosis. At the end of meiotic prophase, they undergo the final meiotic division to form haploid spermatids. These spermatids undergo spermiogenesis to form mature spermatozoa [3]. This complex process is orchestrated through expression of thousands of genes encoding proteins which are developmentally regulated during spermatogenesis and play essential roles during specific phases of germ cell development. Both transcriptional and translational control mechanisms are responsible for temporal and stage-specific expression pattern of genes [4,5].