Localization of a spermatid-specific histone 2B protein in mouse spermiogenic cells.
Localization of a spermatid-specific histone 2B protein in mouse spermiogenic cells.
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DOI：
10.1095/biolreprod48.5.1047
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发表时间：
1993-05
影响因子：
3.6
通讯作者：
S. B. Moss;J. Orth
中科院分区：
文献类型：
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作者：
S. B. Moss;J. Orth
哺乳动物精子发生的特征是染色质浓缩，细胞核中的精蛋白取代体细胞和早期生精细胞的典型组蛋白。然而，精子细胞特异性的H2 b组蛋白（ssH 2b），具有一个不寻常的羧基末端含有一个区域丰富的疏水氨基酸的转录和翻译在小鼠圆形精子细胞。该区域的疏水性表明，该蛋白可能定位于核膜，在精子发生过程中的染色质凝聚的初始站点。为了鉴定精子细胞核中的ssH 2b，针对对应于该蛋白的独特羧基末端的合成肽产生抗血清（抗ss-H2 b127 -138）。固定，冷冻睾丸切片在光镜和电镜水平的免疫细胞化学表明，ssH 2b是存在于圆形精子细胞的细胞核。此外，蛋白质没有被发现是优先与核膜，表明它是不参与染色质核膜的相互作用在圆形精子细胞。相反，它似乎均匀地分布在整个细胞核中，除了它被排除在核仁之外。此外，ssH 2b蛋白在成熟精子中没有发现，即使当染色质部分去致密化，这表明它是存在的，功能仅在有限的生精发育期间。
Mammalian spermiogenesis is characterized by chromatin condensation and replacement of the histones typical of somatic and earlier spermatogenic cells by protamines in the nucleus. However, a spermatid-specific H2b histone (ssH2b) that has an unusual carboxyl-terminus containing a region rich in hydrophobic amino acids is transcribed and translated in mouse round spermatids. The hydrophobicity of this region suggested that the protein may be localized at the nuclear envelope, the initial site of chromatin condensation during spermiogenesis. To identify ssH2b in the spermatid nucleus, an antiserum (anti-ss-H2b127-138) was generated against a synthetic peptide corresponding to the unique carboxyl-terminus of the protein. Immunocytochemistry of fixed, frozen testicular sections at both the light and electron microscopic levels indicated that ssH2b is present in nuclei of round spermatids. Moreover, the protein was not found to be preferentially associated with the nuclear envelope, indicating that it is not involved in chromatin-nuclear envelope interaction in the round spermatid. Rather, it appeared to be distributed uniformly throughout the nucleus with the exception of its exclusion from the nucleolus. In addition, the ssH2b protein was not found in mature sperm even when the chromatin was partially decondensed, suggesting that it is present and functions only during a restricted period of spermatogenic development.