During spermatogenesis, changes in sperm nuclear morphology are associated with the replacement of core somatic histones by protamines. Although protamines are the major nucleoproteins of mature sperm, not all species totally replace the histones. Histone H1, along with protamines, mediates chromatin condensation into an insoluble complex that is transcriptionally inactive. In vitro, heparin-reduced glutathione causes sperm decondensation, and the structures formed are morphologically similar to the in vivo male pronucleus. To study the participation of histone H1 in bovine sperm chromatin remodelling, we measured the presence and release of histone H1 by immunofluorescence, acetic acid-urea-triton-polyacrylamide gel electrophoresis, and immunoblotting. Nuclear decondensation was induced by 80 microM heparin and 15.0 mM reduced glutathione (GSH) for 7, 14, and 21 h at 37 degrees C. Additionally, nucleons, composed of nuclei isolated from the sperm, were decondensed with 20.0 microM heparin and 5.0 mM GSH for 4.0 h at 37 degrees C. Controls were incubated in buffer for similar periods of time. Immunofluorescent localization of histone H1 was carried out with mouse monoclonal antibody, and DNA localization was visualized by 0.001% quinacrine staining. Chromatin decondensation was accompanied by increased sperm nuclei and nucleon surface area. We observed that histone H1 was localized exclusively in the nuclei of intact sperm and nucleons. Histone H1 immunofluorescent intensity did not change in control samples but decreased over time in samples treated with heparin-GSH. There was a negative correlation between the surface area of sperm nuclei and immunohistochemical intensity of histone H1 (P < 0.05). Nucleon decondensation showed a similar relationship. By electrophoresis and immunoblotting, we verified the loss of histone H1 from the sperm and nucleons and its release into the incubation media. Based on these results, we propose that histone H1 is present in the bovine sperm nuclei. H1 depletion may participate in chromatin decondensation and nuclear swelling induced by heparin-GSH.

中文翻译：

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肝素-谷胱甘肽在染色质缩合过程中牛精子组蛋白H1的存在和释放。

在精子发生过程中，精子核形态的变化与鱼精蛋白替代核心体细胞组蛋白有关。尽管鱼精蛋白是成熟精子的主要核蛋白，但并非所有物种都能完全取代组蛋白。组蛋白H1与鱼精蛋白一起将染色质缩合介导为不具有转录活性的不溶复合物。在体外，肝素还原型谷胱甘肽可引起精子解聚，形成的结构在形态上与体内雄性原核相似。为了研究组蛋白H1在牛精子染色质重塑中的参与，我们通过免疫荧光，乙酸-尿素-triton-聚丙烯酰胺凝胶电泳和免疫印迹法测量了组蛋白H1的存在和释放。80 microM肝素和15诱导肝细胞核脱凝。0 mM还原的谷胱甘肽（GSH）在37摄氏度下进行7、14和21小时。此外，在37摄氏度下，将由从精子中分离出的核组成的核子与20.0 microM肝素和5.0 mM GSH进行缩合4.0小时。将对照在缓冲液中温育相似的时间段。用小鼠单克隆抗体进行组蛋白H1的免疫荧光定位，并通过0.001％奎纳克林染色观察DNA定位。染色质的缩聚伴随着精子核和核子表面积的增加。我们观察到，组蛋白H1仅定位在完整的精子和核子的核中。对照样品中的组蛋白H1免疫荧光强度没有变化，但在经过肝素GSH处理的样品中随时间的推移而降低。精子核表面积与组蛋白H1的免疫组化强度呈负相关（P <0.05）。核子缩聚显示出相似的关系。通过电泳和免疫印迹，我们验证了精子和核仁中组蛋白H1的损失以及其释放到培养液中的能力。基于这些结果，我们建议组蛋白H1存在于牛精子核中。H1耗竭可能参与肝素-GSH诱导的染色质浓缩和核肿胀。我们建议组蛋白H1存在于牛精子核中。H1耗竭可能参与肝素-GSH诱导的染色质浓缩和核肿胀。我们建议组蛋白H1存在于牛精子核中。H1耗竭可能参与肝素-GSH诱导的染色质浓缩和核肿胀。