Identification and characterization of a haploid germ cell-specific nuclear protein kinase (Haspin) in spermatid nuclei and its effects on somatic cells
Identification and characterization of a haploid germ cell-specific nuclear protein kinase (Haspin) in spermatid nuclei and its effects on somatic cells
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DOI：
10.1074/jbc.274.24.17049
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发表时间：
1999-06-11
影响因子：
4.8
通讯作者：
Nishimune, Y
中科院分区：
文献类型：
--
作者：
Tanaka, H;Yoshimura, Y;Nishimune, Y
我们克隆了小鼠生殖细胞特异性cDNA的整个编码区，该cDNA编码一种独特的蛋白激酶，其催化结构域仅包含三个共识亚结构域（I-III），而不是正常的12个。该蛋白质具有内在的Ser/Thr激酶活性，并且仅在单倍体生殖细胞中表达，仅定位于其细胞核中，因此被命名为Haspin（haploid germ cell-Specific nuclear protein kinase）。Westernblot分析表明，特异性抗体识别睾丸中的M-r 83，000蛋白，Haspin仅在培养的体细胞核中表达，即使在没有激酶活性的情况下，Haspin也能使细胞周期停滞在G（1），导致转染体细胞生长停滞。在DNA结合实验中，大约一半的野生型Haspin能够与DNA-纤维素柱结合，而另一半则不能。相反，所有缺乏自磷酸化的缺失突变体Haspin都与DNA柱结合。因此，Haspin的DNA结合活性可能以某种方式与其激酶活性相关。这些观察结果表明，Haspin在细胞周期停止和单倍体生殖细胞的分化中具有一些关键作用。
We have cloned the entire coding region of a mouse germ cell-specific cDNA encoding a unique protein kinase whose catalytic domain contains only three consensus subdomains (I-III) instead of the normal 12. The protein possesses intrinsic Ser/Thr kinase activity and is exclusively expressed in haploid germ cells, localizing only in their nuclei, and was thus named Haspin (for haploid germ cell-Specific nuclear protein kinase). Western blot analysis showed that specific antibodies recognized a protein of M-r 83,000 in the testis, Ectopically expressed Haspin was detected exclusively in the nuclei of cultured somatic cells, Even in the absence of kinase activity, however, Haspin caused cell cycle arrest at G(1), resulting in growth arrest of the transfected somatic cells. In a DNA binding experiment, approximately one-half of wild-type Haspin was able to bind to a DNA-cellulose column, whereas the other half was not. In contrast, all of the deletion mutant Haspin that lacked autophosphorylation bound to the DNA column. Thus, the DNA-binding activity of Haspin may, in some way, be associated with its kinase activity. These observations suggest that Haspin has some critical roles in cell cycle cessation and differentiation of haploid germ cells.