Identification of a heat-shock protein Hsp40, DjB1, as an acrosome- and a tail-associated component in rodent spermatozoa
Identification of a heat-shock protein Hsp40, DjB1, as an acrosome- and a tail-associated component in rodent spermatozoa
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DOI：
10.1002/mrd.20609
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发表时间：
2007-02-01
影响因子：
2.5
通讯作者：
Iida, Hiroshi
中科院分区：
文献类型：
--
作者：
Doiguchi, Masamichi;Kaneko, Takane;Iida, Hiroshi
lba 1是一个17-kDa的EF-手蛋白，在睾丸中伸长精子细胞的细胞质中高度表达。以Iba 1为诱饵，通过酵母双杂交筛选，从小鼠睾丸cDNA文库中分离到一个热休克蛋白Hsp 40，DjB 1。为了表征Dnajb 1基因编码的DjB 1，我们进行了免疫印迹分析，原位杂交和免疫组织化学。免疫印迹分析表明，DjB 1在小鼠睾丸中组成型表达，其表达水平不受热休克的影响。在小鼠睾丸中，Dnajb 1 mRNA仅在精母细胞和圆形精子细胞中表达，Dnajb 1蛋白DjB 1主要在精母细胞、圆形精子细胞和伸长精子细胞的胞质中表达。在成熟的小鼠精子中，DjB 1定位于鞭毛的中部和末端以及与头部（顶体区域）的关联。在大鼠精子中也观察到DjB 1与精子头部顶体区域的关联。这些数据表明，DjB 1，这是组成型表达在精巢的减数分裂后的生精细胞，被整合到精子中的至少两个组件，即精子的头部和尾部的啮齿动物精子。
lba1 is a 17-kDa EF-hand protein highly expressed in the cytoplasm of elongating spermatids in testis. Using Iba1 as a bait, we performed yeast Two-hybrid screening and isolated a heat-shock protein Hsp40, DjB1, from cDNA library of mouse testis. To characterize DjB1 that is encoded by Dnajb1 gene, we carried out immunoblot analyses, in situ hybridization, and immunohistochemistry. Immunoblot analyses showed that DjB1 was constitutively expressed in mouse testis and that its expression level was not changed by heat shock. Dnajb1 mRNA was exclusively expressed in spermatocytes and round spermatids in mouse testis, and Dnajb1 protein DjB1 was predominantly expressed in the cytoplasm of spermatocytes, round spermatids, and elongating spermatids. In mature mouse spermatozoa, DjB1 was localized in the middle and the end pieces of flagella as well as in association with the head (acrosomal region). Association of DjB1 with the acrosomal region in sperm head was also observed in rat spermatozoa. These data suggested that DjB1, which was constitutively expressed in postmeiotic spermatogenic cells in testis, was integrated into spermatozoa as at least two components, that is, sperm head and tail of rodent spermatozoa.