Wu L H, Kuehl L, Rechsteiner M
J Cell Biol. 1986 Aug;103(2):465-74. doi: 10.1083/jcb.103.2.465.
Histone H1 was purified from bovine thymus and radiolabeled with tritium by reductive methylation or with 125I using chloramine-T. Red blood cell-mediated microinjection was then used to introduce the labeled H1 molecules into HeLa cells synchronized in S phase. The injected H1 molecules rapidly entered HeLa nuclei, and a number of tests indicate that their association with chromatin was equivalent to that endogenous histone H1. The injected molecules copurified with HeLa cell nucleosomes, exhibited a half-life of approximately 100 h, and were hyperphosphorylated at mitosis. When injected HeLa cells were fused with mouse 3T3 fibroblasts less than 10% of the labeled H1 molecules migrated to mouse nuclei during the next 48 h. Thus, the intracellular behavior of histone H1 differs markedly from that of high mobility group proteins 1 and 2 (HMG1 and HMG2), which rapidly equilibrate between human and mouse nuclei after heterokaryon formation (Rechsteiner, M., and L. Kuehl, 1979, Cell, 16:901-908; Wu, L., M. Rechsteiner, and L. Kuehl, 1981, J. Cell Biol, 91: 488-496). Despite their slow rate of migration between nuclei, the injected H1 molecules were evenly distributed on mouse and human genomes soon after mitosis of HeLa-3T3 heterokaryons. These results suggest that although most histone H1 molecules are stably associated with interphase chromatin, they undergo extensive redistribution after mitosis.
组蛋白H1从牛胸腺中纯化出来，通过还原甲基化用氚进行放射性标记，或用氯胺-T用125I进行标记。然后使用红细胞介导的显微注射将标记的H1分子引入同步于S期的HeLa细胞。注入的H1分子迅速进入HeLa细胞核，多项测试表明它们与染色质的结合与内源性组蛋白H1相当。注入的分子与HeLa细胞核小体共纯化，半衰期约为100小时，并且在有丝分裂时发生超磷酸化。当注入的HeLa细胞与小鼠3T3成纤维细胞融合时，在接下来的48小时内，不到10%的标记H1分子迁移到小鼠细胞核中。因此，组蛋白H1的细胞内行为与高迁移率族蛋白1和2（HMG1和HMG2）明显不同，后者在异核体形成后在人和小鼠细胞核之间迅速平衡（Rechsteiner，M.，和L. Kuehl，1979年，《细胞》，16:901 - 908；Wu，L.，M. Rechsteiner，和L. Kuehl，1981年，《细胞生物学杂志》，91: 488 - 496）。尽管它们在细胞核之间的迁移速度较慢，但在HeLa - 3T3异核体有丝分裂后不久，注入的H1分子在小鼠和人类基因组上均匀分布。这些结果表明，尽管大多数组蛋白H1分子与间期染色质稳定结合，但它们在有丝分裂后会经历广泛的重新分布。
