Ubiquitination of histone H3 in elongating spermatids of rat testes
Ubiquitination of histone H3 in elongating spermatids of rat testes
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DOI：
10.1074/jbc.273.21.13165
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发表时间：
1998-05-22
影响因子：
4.8
通讯作者：
Meistrich, ML
中科院分区：
文献类型：
--
作者：
Chen, HY;Sun, JM;Meistrich, ML
由于组蛋白泛素化在改变染色质结构中的潜在作用，我们通过二维凝胶电泳表征了大鼠睾丸减数分裂和减数分裂后生殖细胞中特定组蛋白的泛素化水平，主要的泛素化组蛋白形式，单和多泛素化H2A的水平在粗粒精细胞阶段最高，随后在圆形精细胞阶段下降，在细长精细胞阶段达到最低水平。除H2A外，我们还利用抗泛素抗体检测到另外三种泛素化组蛋白，这些泛素化组蛋白在细长精子中富集。根据它们的电泳迁移率，它们分别对应于uH3、uTH3和uH2B。这些蛋白的多泛素化形式也被观察到。通过抗h3抗血清免疫印迹和随着盐浓度的增加从细胞核中提取不同的蛋白，证实了这些蛋白的身份。这是首次报道H3在体内泛素化。我们推测，它的泛素化可能使核小体结构松动，为组蛋白去除做准备，也可能是核小体松弛或其他方式引起的破坏的结果，或者是靶向H3进行降解。
Because of the potential role of histone ubiquitination in altering chromatin structure, we characterized the levels of ubiquitination of specific histones in meiotic and postmeiotic germ cells in rat testes by two-dimensional gel electrophoresis, The levels of the major ubiquitinated histone forms, mono-and poly-ubiquitinated H2A, were highest in the pachytene spermatocyte stage, declined thereafter through the round spermatid stage, and reached their lowest levels in elongating spermatids. Three additional ubiquitinated histone species, besides H2A, were detected using anti-ubiquitin antibodies specifically in the fraction enriched in elongating spermatids. Based on their electrophoretic mobilities, they corresponded to uH3, uTH3, and uH2B. Polyubiquitinated forms of these proteins were also observed. The identity of these proteins was confirmed by immunoblotting with anti-H3 antisera and by differential extraction of the proteins from the nucleus with increasing salt concentrations. This is the first report of ubiquitination of H3 in vivo. We speculate that its ubiquitination could loosen the nucleosome structure in preparation for histone removal, be a consequence of nucleosome relaxation or disruption caused by other means, or target H3 for degradation.