Haprin, a novel haploid germ cell-specific RING finger protein involved in the acrosome reaction
Haprin, a novel haploid germ cell-specific RING finger protein involved in the acrosome reaction
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DOI：
10.1074/jbc.m304306200
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发表时间：
2003-11-07
影响因子：
4.8
通讯作者：
Nishimune, Y
中科院分区：
文献类型：
--
作者：
Kitamura, K;Tanaka, H;Nishimune, Y
顶体反应（即精子囊泡的胞吐作用）是受精的先决条件，但其分子机制在很大程度上是未知的。我们已经确定了一个名为haprin，它编码一个单倍体生殖细胞特异性环指蛋白基因的cDNA克隆。该蛋白是RBCC（RING finger，B-box type zinc finger，and coiled-coil domain）基序家族的新成员，其在几种细胞过程中发挥作用，例如胞吐作用。它只在减数分裂后的睾丸生殖细胞中转录。Western blot和免疫组化分析表明Haprin蛋白的分子量为M-r，接近82，000。它定位于长形精子细胞和成熟精子的顶体区，而不存在于顶体反应精子。针对Haprin的RING指结构域的特异性抗体抑制透化精子中的顶体反应。这些结果表明，新的RBCC蛋白Haprin在顶体反应和受精中起着关键作用。
The acrosome reaction (i.e. the exocytosis of the sperm vesicle) is a prerequisite for fertilization, but its molecular mechanism is largely unknown. We have identified a cDNA clone for a gene named haprin, which encodes a haploid germ cell-specific RING finger protein. This protein is a novel member of the RBCC (RING finger, B-box type zinc finger, and coiled-coil domain) motif family that has roles in several cellular processes, such as exocytosis. It is transcribed exclusively in testicular germ cells after meiotic division. Western blot and immunohistochemical analyses showed the molecular weight of Haprin protein to be M-r similar to 82,000. It was localized in the acrosomal region of elongated spermatids and mature sperm and was not present in acrosome-reacted sperm. The specific antibody against the RING finger domain of Haprin inhibited the acrosome reaction in permeabilized sperm. These results indicated that the novel RBCC protein Haprin plays a key role in the acrosome reaction and fertilization.