Catena Raffaella, Ronfani Lorenza, Sassone-Corsi Paolo, Davidson Irwin
Institut de Génétique et de Biologie Molécularie et Cellulaire, CNRS/INSERM/ULP, 1 Rue Laurent Fries, 67404 Illkirch Cedex, France.
Dev Biol. 2006 Aug 1;296(1):231-238. doi: 10.1016/j.ydbio.2006.04.458.
Spermiogenesis entails a major biochemical and morphological restructuring of the germ cell packing the DNA into the condensed spermatid nucleus. H1T2 is a histone H1 variant selectively and transiently expressed in male haploid germ cells during spermiogenesis that specifically localizes to a chromatin domain at the apical pole under the acrosome. We explored the mechanisms determining polar localization of H1T2 in spermatids. In acrosome-deficient round spermatids of hrb -/- and gopc -/- mice, H1T2 localization is not altered, indicating that proper acrosome development is not required for specifying nuclear polarity. In contrast, in late round spermatids from trf2 -/- or hmgb2 -/- mice, a bipolar H1T2 localization was observed revealing that polarity is modified by loss of proteins specifying chromatin architecture. Our results show that intranuclear chromatin organization is critical for correct polar localization of H1T2 and that H1T2 can be a useful molecular marker revealing chromatin disorganization in spermatids.
精子发生过程涉及生殖细胞的重大生化和形态重构，即将DNA包装进浓缩的精子细胞核中。H1T2是一种组蛋白H1变体，在精子发生过程中于雄性单倍体生殖细胞中选择性且短暂地表达，它特异性地定位于顶体下方顶端极的染色质结构域。我们探究了决定H1T2在精子细胞中极性定位的机制。在hrb-/-和gopc-/-小鼠的顶体缺陷圆形精子细胞中，H1T2的定位未改变，这表明正确的顶体发育对于确定核极性并非必需。相反，在trf2-/-或hmgb2-/-小鼠的晚期圆形精子细胞中，观察到H1T2的双极定位，这表明极性会因指定染色质结构的蛋白质缺失而改变。我们的结果表明，核内染色质组织对于H1T2的正确极性定位至关重要，并且H1T2可以作为揭示精子细胞中染色质紊乱的有用分子标记。
