The major subacrosomal occupant of bull spermatozoa is a novel histone H2B variant associated with the forming acrosome during spermiogenesis
The major subacrosomal occupant of bull spermatozoa is a novel histone H2B variant associated with the forming acrosome during spermiogenesis
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DOI：
10.1006/dbio.2001.0427
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发表时间：
2001-11-15
影响因子：
2.7
通讯作者：
Oko, RJ
中科院分区：
文献类型：
--
作者：
Aul, RB;Oko, RJ
最近对哺乳动物精子头部结构组成的研究表明，一种未知蛋白质聚集在哺乳动物精子核的外围，形成一层凝聚的细胞质。这些蛋白质是核周膜（PT），可分为sds可溶性和sds不溶性组分。本研究的重点是鉴定主要的sds不溶性PT蛋白，我们定位于牛精子顶体下层，并通过免疫筛选公牛睾丸cDNA文库克隆。分离的克隆编码一个122个氨基酸的蛋白，与组蛋白H2B具有67%的相似性，并包含一个预测的组蛋白折叠基序。该蛋白的新氨基端包含一个潜在的二部核靶向序列。因此，我们确定了这种突出的顶体下成分是一种新的H2B变体，SubH2Bv。对SubH2Bv mRNA表达的Northern blot分析显示，它是睾丸特异性的，也存在于小鼠睾丸中。免疫细胞化学分析显示，SubH2Bv在时间和空间上与顶体形成密切相关。虽然SubH2Bv的分子特征与核蛋白是共同的，但它从未在精细胞的细胞核中发育。考虑到其发育和分子特性，我们假设SubH2Bv在顶体组装和顶体-核对接中起作用。(C) 2001学术出版社。
Recent studies on the structural composition of mammalian sperm heads have shown a congregate of unidentified proteins occupying the periphery of the mammalian sperm nucleus, forming a layer of condensed cytosol. These proteins are the perinuclear theca (PT) and can be categorized into SDS-soluble and SDS-insoluble components. The present study focused on identifying the major SDS-insoluble PT protein, which we localized to the subacrosomal layer of bovine spermatozoa and cloned by immunoscreening a bull testicular cDNA library. The isolated clones encode a protein of 122 amino acids that bears 67% similarity with histone H2B and contains a predicted histone fold motif. The novel amino terminus of the protein contains a potential bipartite nuclear targeting sequence. Hence, we identified this prominent subacrosomal component as a novel H2B variant, SubH2Bv. Northern blot analyses of SubH2Bv mRNA expression showed that it is testis-specific and is also present in murid testes. Immunocytochemical analysis showed SubH2Bv intimately associates, temporally and spatially, with acrosome formation. While the molecular features of SubH2Bv are common to nuclear proteins, it is never seen developmentally within the nucleus of the spermatid. Considering its developmental and molecular characteristics, we have postulated roles of SubH2Bv in acrosome assembly and acrosome-nuclear docking. (C) 2001 Academic Press.