Sperm Proteomics: Road to Male Fertility and Contraception

Figure 1

Schematic diagram showing the cellular, genetic, and chromatin changes during spermatogenesis. (a) The figure represents the cellular changes during spermatogenesis coupled with its genetic modifications. Following spermatogenesis, the male primordial germ cells, spermatogonia, first differentiate to primary spermatocytes and undergo genetic recombination to produce haploid round spermatids. The round spermatids then participate in another differentiation process to produce the mature spermatozoa. For successful fertilization, mammalian spermatozoa undergo first capacitation and then the acrosome reaction, which collectively allows spermatozoa to penetrate the zona pellucida and to fuse with the oocyte plasma membrane both in vivo and in vitro. (b) The figure shows chromatin changes that cause the transition of the mammalian nucleohistone to nucleoprotamine [17, 18]. In addition, the Donut-Loop model has been inserted at the end to represent the internal structure of the protamine-DNA fibers inside the toroid [17, 18]. The red color indicates histones and the blue color indicates DNA.