小麦TOM7蛋白类似基因的克隆与分析

通过RT—PCR技术分离了编码小麦线粒体蛋白转运酶TOM7亚基(Translocase of Outer Mitochondrial Membrane subunit 7)的cDNA，并克隆了该基因编码区的基因组DNA，将该基因命名为TaTOM7。TaTOM7是一个没有内含子的基因，其编码的多肽具有一个位于中部的疏水跨膜区和两个分别位于N-端和C-端的亲水区域。来源于真菌、动物和植物的TOM7类似蛋白在疏水跨膜区高度保守，而在亲水区变异很大。在系统发育树中，TOM7类似蛋白可以按动物、植物和真菌分为3个类群。小麦TaTOM7在基因组中以寡拷贝形式存在，它的表达在Ms2近等基因系之间和不同组织之间存在差异。中国春缺体一四体及端二体系分析表明，TaTOM7位于小麦第3染色体同源群。

Cloning and Characterization of TOM7-like Gene in Wheat

The cDNA encoding TOM7 (translocase of outer mitochondrial membrane subunit 7) like protein in wheat was cloned through RT-PCR,and its genomic DNA fragment was subsequently cloned.This gene was tentatively designated as TaTOM7.It has no intron in the coding region and its product possesses one hydrophobic trans-membrane domain in the middle,and one hydrophilic domain in the N-terminal and C-terminal domain,respectively.The amino acid composition in the trans-membrane domain of the TaTOM7 subunit is highly conserved among plants,animals and fungi.According to the phylogenetic tree,TOM7-like proteins from different species can be classified into three groups,representing plants,animals and fungi respectively.TaTOM7 is a single- or oligo-copy gene in the wheat genome,displaying different expression levels between Ms2 near-isogenic lines in some tissues,suggesting a role of Ms2 in its expression.TaTOM7 was mapped to chromosome group three of wheat.