山羊金属硫蛋白-Ⅲ基因克隆及序列分析

Cloning and Sequence Analysis of Metallothionein-Ⅲ in Goat

通过设计特异性引物MT-ⅢSP1和MT-ⅢSP2,采用RT-PCR方法从山羊脑组织中克隆出金属硫蛋白-Ⅲ(MT-Ⅲ)基因编码区全序列,片段长度均为207 bp,提交GenBank,登录号为:EF471976。山羊MT-Ⅲ基因编码68个氨基酸,含19个半胱氨酸,不含芳香族氨基酸和组氨酸。BLAST比对结果表明,山羊与牛、绵羊、狗、猪、人、黑猩猩和鼠的氨基酸同源性分别为99.5%、98.6%、89.4%、88.5%、88.2%、88.2%和83.8%,说明MT-Ⅲ在物种间高度同源,进化上高度保守,含有MT-Ⅲ特有的MDPET、C-X-C、C-C-X-C-C、C-X-X-C、KKS(X为非Cys外的其它氨基酸)等保守的短肽结构。系统进化树结果表明,由核苷酸序列与氨基酸序列建立的系统进化树结果一致,并与比较形态学和比较生理学分类结果一致。

In this study,a pair of special primers（MT-ⅢSP1 and MT-ⅢSP2） were designed for cloning the coding sequence of metallothionien-Ⅲ（MT-Ⅲ） from brain tissue in goat.The MT-Ⅲ coding sequence in goat were 207 bp.The goats MT-Ⅲ gene sequences had been submitted to GenBank under accession numbers EF471976.Goat MT-Ⅲ gene coded 68 amino acids,including 19 Cys residues.Goat MT-Ⅲ had characteristic MDPET,C-X-C,C-C-X-C-C,C-X-X-C and KKS sequences of MTs,where X was non-cysteine amino acids.The amino acids sequences of goat shared 99.5%,98.6%,89.4%,88.5%,88.2%,88.2% and 83.8% sequence similarity with cattle,sheep,dog,pig,human,rhesus monkey and mouse,it showed that the MT-Ⅲ was very conservative.The phylogeny of MT-Ⅲ from nucleotide and amino acids sequence were same,and was also consistent with the result of morphology and physiology.