中文摘要：

对克隆的拟态弧菌Vibrio mimicus的全长toxR基因及进行相关的序列分析。根据已发表的其他几种弧菌toxR基因两翼核苷酸序列，设计和合成上下游简并引物，以拟态弧菌1.1969标准株的基因组DNA为模板进行PCR扩增，将获得的1.3kb扩增片断进行克隆、鉴定和测序，并将该序列提交至GenBank（登录号为EF693743）。首次获得拟态弧菌840bptoxR基因全长核苷酸序列。与其它弧菌的相应序列分析比对显示，该序列与霍乱弧菌Vibrlo cholerae的toxR基因有87％-88％的相似性，与鳗弧菌Vibrio anguillarum的toxR基因有75％的相似性，与副溶血弧菌Vibrio parahaemolyticus的toxR基因有45％的相似性。该基因编码1个含有279个氨基酸残基的蛋白质，其分子量为31．13kDa，等电点为5．35，并含有一个典型的转录激活区和一个跨膜区。系统发育树分析表明，几种常见致病性弧菌的toxR基因序列存在较大分歧，拟态弧菌能较容易与进化相近的霍乱弧菌鉴别区分开来。toxR基因全长核苷酸序列的获得将为拟态弧菌的菌种鉴定增添新的分子靶标，有助于其结构和功能的研究及通过突变分析鉴定出新的受toxR基因调控的致病基因。

英文摘要：

The purpose of this study was to isolate the complete gene sequence of the toxR gene of Vibrio mimicus by PCR using degenerate primers. The degenerate primers were designed based on known flanking toxR gene sequences of several Vibrio spp. The resulting approximately 1.3kb amplicon was cloned and sequenced. The sequence of the toxR gene of Vibrio mimicus was deposited in the GenBank database under accession number EF693743. This paper reported, for the first time, a complete 840bp nucleotide sequence of toxR gene of Vibrio mimicus. Sequence analysis and alignment of the toxR nucleotide sequence from Vibrio mimicus with those from other Vibrio species revealed that the complete toxR gene of Vibrio mimicus shares 87%-88% sequence similarity with the toxR gene of Vibrio cholerae, 75% with Vibrio anguillarum, and 45% with Vibrio parahaemolyticus. It encoded a 279 aa protein as expected. The deduced protein, with molecular weight of 31.13kDa and IP of 5.35, included a typical transcriptional activation domain and a transmembrane region. The phylogenetic trees revealed a wide divergence in toxR among several common pathogenic vibrios, and Vibrio mimicus could be easily distinguished from its close species Vibrio cholera. The information from the complete toxR sequence, which may be a good target for species identification of Vibrio mimicus, would promote structure function studies and mutation analysis so as to identify toxR-regulated genes.