人Collectrin同源基因的分离克隆及其在人肾集合管和远曲小管的特异表达

为探讨collectrin在人类疾病中的作用 ,利用人类collectrin同源性引物 ,经末端cDNA快速扩增法分离获得人collectrin基因全长序列并对collectrin进行生物信息学分析及定位表达研究 .结果发现 ,人类collectrin(GenBank登录号为AF2 2 9179)基因全长含 1345bp ,开放阅读框架编码 2 2 2个氨基酸 .在核苷酸和氨基酸水平 ,与小鼠collectrin序列分别有 86 9%和 87 4 %同源性 .生物信息学分析结果提示 ,collectrin为一个 2 5kD的具有一个信号肽和一个跨膜区的跨膜糖蛋白 .人类collectrin与人类血管紧张素转换酶相关的羧基肽酶 (ACE2 )具有 4 7 8%高度同源性 .人多组织Northern杂交结果显示 :collectrin基因为人类肾脏特异性表达基因 .原位杂交及免疫组化证实 ,与小鼠collectrin特异表达于集合管细胞不同 ,人collectrin基因mRNA及其蛋白产物除位于肾脏集合管细胞外 ,远曲肾小管细胞也有表达 .由此推论 ,人类collectrin基因为肾脏特异性表达基因 ,与人类血管紧张素转换酶相关的羧基肽酶具有高度同源性 ,可能为血管紧张素转换酶 (ACE)基因家族的新成员 .

Identification and Localization of Human Collectrin in Normal Kidney

To identify human homologue gene of collectrin, which is a kidney-specific novel gene cloned in 5/6 ablated mouse kidney, rapid amplification of cDNA end PCR (RACE-PCR) with human collectrin homologous primers were performed and its distribution and expression were further investigated. The full-length cDNA of human collectrin (GenBank No. AF229179) is 1345 bp, and it encodes 222 amino acid residues. The sequence is conserved in mouse and human, which shares 86.9% identity in nucleotide and 87.4% in amino acid between mouse and human. Bioinformatical analysis demonstrates that collectrin contains a signal peptide and a trans-membrane domain with a predicted molecular mass of 25 kD. It has 47.8% homology with ACE2, which was recently identified as a novel member of ACE gene family. Multiple tissue Northern blot reveals that collectrin was only detectable in the kidney. In situ hybridization and immunohistochemical staining show that human collectrin exists in renal collecting ducts, as well as in distal tubules. Human collectrin is a kidney-specific novel gene expressed in collecting ducts and distal tubules. The result implied that human collectrin might be a novel member of ACE gene family with its sequence highly homologue with ACE2.