Abstract: AiiA, encoded by aiiA gene is one of the homoserine lactone enzyme that can hydrolyze the AHL on the lactone ring of Gram-negative bacteria. Coding sequence of aiiA gene from Bacillus thuringiensis was analyzed by CodonW, CUSP and CHIPS programs for identifying codon bias. Comparing the codon usage of aiiA gene with genomic codon usage of Escherichia coli, Bacillus thuringiensis, Bacillus subtilis and Pichia pastoris, it was indicated that aiiA gene prefers to use the codons ended with A or T; codon bias of aiiA gene from Bacillus thuringiensis was significantly different from those of E.coli, Bacillus subtilis and Pichia pastoris. The result of comparing the usage frequency of aiiA gene in four different hosts showed that there were different degrees of low frenquency regions. The analytic result was very important guideline for designing the aiiA gene to improve the expression of AiiA in those four express systems.

Key words: Bacillus thuringiensis, aiiA gene, codon usage bias, codon optimization, heterogeneous expression

摘要： aiiA基因指导表达的AiiA蛋白是一类能水解细菌群体感应信号分子内酯键的内酯酶。本研究使用CodonW、CUSP和CHIPS等相关程序对苏云金芽胞杆菌中aiiA基因的密码子使用情况进行分析，比较了aiiA基因与大肠杆菌、苏云金芽胞杆菌、枯草芽胞杆菌以及毕赤酵母的密码子偏好性。结果表明，aiiA基因偏好使用以A、T结尾的密码子；aiiA基因的密码子用法与大肠杆菌、苏云金芽胞杆菌、枯草芽胞杆菌和毕赤酵母的基因组密码子用法都有不同程度的偏好差异，其中与毕赤酵母的密码子用法差异最大；比较了aiiA基因分别以苏云金芽胞杆菌、大肠杆菌、枯草芽胞杆菌及毕赤酵母为宿主时密码子使用频率，发现都含有不同程度的低频密码子聚集现象，如果要在上述几种表达系统中实现aiiA基因的高效表达则需对aiiA基因的部分密码子进行优化改造。

关键词: 苏云金芽胞杆菌, aiiA基因, 密码子偏好性, 密码子优化, 异源表达