Chapter 2 Biochemistry of Male Germ Cell Differentiation in Mammals: RNA Synthesis in Meiotic and Postmeiotic Cells

Abstract

This chapter discusses a few aspects of ribonucleic acid (RNA) and protein synthesis at different stages of germ cell differentiation in mammals that are relevant to the problem of regulation of spermatogenesis. Spermatogenesis is a highly orderly process that begins with the stem cell and terminates with the release of the mature spermatid into the lumen of the seminiferous tubule. In the mouse, the total duration of spermatogenesis, from the stem cell to the mature spermatid, is about 34.5 days and is subdivided into three phases: (1) the period of multiplication and maturation of spermatogonia or mitotic phase of spermatogenesis that lasts about eight days, (2) meiosis that lasts 13 days, and (3) spermiogenesis, from the early spermatid to the release of the spermatozoon into the lumen, which is about 13.5 days long. Biochemistry of spermatogenesis is one of the most promising areas of research in developmental biology and mammalian reproduction. The development of germ cell is a field, where different experimental approaches, cytology, ultrastructure, cytogenetics, genetics, biochemistry, immunology, endocrinology, can interact in a coordinated view of cell differentiation. The results described provide clear evidence for gene expression during the haploid phase of spermatogenesis in the mouse; the transcriptional activity during early spermiogenesis involves both polyadenylated RNA and ribosomal RNA.