疣粒野生稻泛素结合酶基因的全长cDNA序列克隆与分析

Cloning and Analysis on Full-Length Cdna Sequence of Ubiquitin-Conjugating Enzyme Gene from Oryza meyeriana Baill

从已构建的疣粒野生稻消减cDNA文库中随机挑取阳性单克隆经测序得到ESTs,通过生物信息学分析,选取与泛素结合酶具有同源功能的EST以RACE技术分离克隆到1个疣粒野生稻泛素结合酶基因的全长cDNA序列,命名为OmE2(Oryza meyeriana Baill.ubiquitin-conjugating enzyme),该序列长917bp,最大开放阅读框为528bp,编码的蛋白具有175个氨基酸,该蛋白的分子量为19.31kD,理论等电点为9.32。OmE2蛋白与其他物种的泛素结合酶具有高度的一致性和相似性,含有泛素结合酶活性位点的保守序列及半胱氨酸残基,且具有3个跨膜结构域,推测OmE2是一类泛素结合蛋白兼跨膜蛋白。经RT-PCR分析,OmE2基因是受白叶枯病病原菌胁迫诱导表达。这是首次从野生稻中发现可能参与疣粒野生稻胁迫信号传导和抗病应答反应的基因。

Based on the bioinformatic analysis of the ESTs from the subtraction cDNA library of Oryza meyeriana, we cloned one of the ESTs which has the homolog function of ubiquitin-conjugating enzyme and obtained a full-length cDNA sequence of ubiq- uitin-conjugating enzyme gene by RACE, and named it OmE2 （Oryza meyeriana Baill ubiquitin-conjugating enzyme）. This full-length cDNA sequence has 917 bp including 528 bp open reading frame encoding a protein of 175 amino acids, with a pre- dicted molecular mass of 19.3 kD and pl of 9.32. OmE2 protein, which had significant amino sequence identity and similarity with ubiquitin-conjugating enzyme from other species contained the conserved sequence and cysteine residue in the active sites of ubiquitin-conjugating family. OmE2 had three trans-membrane domains. It is predicted that OmE2 protein is a kind of ubiq- uitin-conjugating protein and transmembrane protein. The expression of OmE2 in Oryza meyeriana was induced by Xanthomonas campestris pv. oryzae. Therefore OrnE2 gene which was first found in wild rice may participate in the signal transduction and the resistance response in Oryza meyeriana.