Fig. 8.

Schematic representation of the process of spermiogenesis and chromatin architecture of H1T2 occupied polar apical region of spermatids. a Spermiogenesis is a lengthy post-meiotic developmental process of spermatogenesis in which the round spermatids undergo several morphological and biochemical modifications to form the mature spermatozoa. Substantial remodeling of chromatin during spermiogenesis involves the replacement of standard histones with histone variants (H1t, H1T2, HILS1, H3.3A, and H3.3B) and testes-specific histones (TH2A, TH2B, and TH3) that should favor an open chromatin conformation. Hyperacetylation of H3 and H4 histones probably facilitates the substantial and continuous repackaging of DNA with transition proteins, further replaced by protamines. Leaky transcription of the spermatid genome is considered as a functional consequence of chromatin remodeling in spermatids [121]. b A schematic model showing the involvement of H1T2 in organizing the nucleoskeleton associated active chromatin architecture of the polar apical region of spermatids