—Original Article— Histone H4 Modification During Mouse Spermatogenesis

Abstract. The core histone is composed of four proteins (H2A, H2B, H3 and H4). Investigation of the modification patterns of histones is critical to understanding their roles in biological processes. Although histone modification is observed in multiple cells and tissues, little is known about its function in spermatogenesis. We focused on the modification patterns of histone H4 during murine spermatogenesis. We demonstrated that the individual N-terminal sites of H4 show different modification patterns during the differentiation of male germ cells. The methylation pattern varied depending on the residues that were mono-, di-, or tri-methylated. All the H4 modifications were high during the meiotic prophase, suggesting that histone H4 modification plays an important role during this stage of spermatogenesis. Elongating spermatids showed increased acetylation of histone H4, which may be associated with a histone-to-protamine substitution. Our results provide further insight into the specific relationship between histone H4 modification and gene expression during spermatogenesis, which could help to elucidate the epigenetic disorders underlying male infertility