Matsuyama Takuya, Honda Yoshiko, Doiguchi Masamichi, Iida Hiroshi
Laboratory of Zoology, Graduate School of Agriculture, Kyushu University, Higashiku Hakozaki 6-10-1, Fukuoka, Japan.
Mol Reprod Dev. 2005 Sep;72(1):120-8. doi: 10.1002/mrd.20331.
Tektins are composed of a family of filament-forming proteins associated with ciliary and flagellar microtubules. A new member of the TEKTIN gene family, which was designated as rat Tektin4, was obtained by PCR technique combined with yeast two-hybrid screening. Rat Tektin4 cDNA consists of 1,341 bp encoding a 52 kDa protein of 447 amino acids. Tektin4 protein contains a Tektin domain including a nonapeptide signature sequence (RPNVELCRD), which is a prominent feature of Tektins. Its amino acid sequence showed 29% approximately 58% identities to that of other Tektin family proteins registered in the public databases. Tektin4 gene, which was mapped to rat chromosome 10q12, is composed of six exons and spanning 5 kb. Reverse-transcriptional-PCR (RT-PCR) analysis indicated that Tektin4 was predominantly expressed in testis and its expression was upregulated during testis development. In situ hybridization analysis showed that Tektin4 mRNA was localized in round spermatids in the seminiferous tubules of the rat testis. Tektin4 protein was predominantly localized in the flagella of spermatozoa, suggesting that it might works as a flagellar component requisite for flagellar stability or sperm motility.
纤丝蛋白由一组与纤毛和鞭毛微管相关的丝状形成蛋白组成。通过聚合酶链反应（PCR）技术结合酵母双杂交筛选，获得了TEKTIN基因家族的一个新成员，命名为大鼠纤丝蛋白4（rat Tektin4）。大鼠纤丝蛋白4 cDNA由1341个碱基对组成，编码一个含447个氨基酸的52 kDa蛋白。纤丝蛋白4包含一个纤丝蛋白结构域，其中有一个九肽特征序列（RPNVELCRD），这是纤丝蛋白的一个显著特征。其氨基酸序列与公共数据库中登记的其他纤丝蛋白家族蛋白的氨基酸序列有29%至58%的同源性。纤丝蛋白4基因定位于大鼠染色体10q12，由6个外显子组成，跨度为5 kb。逆转录-聚合酶链反应（RT-PCR）分析表明，纤丝蛋白4主要在睾丸中表达，且在睾丸发育过程中表达上调。原位杂交分析显示，纤丝蛋白4 mRNA定位于大鼠睾丸生精小管中的圆形精子细胞。纤丝蛋白4主要定位于精子的鞭毛，表明它可能作为鞭毛稳定性或精子运动所需的鞭毛成分发挥作用。
