苏云金芽胞杆菌Sigma54和CcpA共同调控的基因鉴定

Identification of genes regulated by Sigma54 and CcpA in Bacillus thuringiensis

摘要:

[目的]通过综合分析苏云金芽胞杆菌（Bacillus thuringiensis） HD73菌株Sigma54缺失突变体的转录组数据和蜡样芽胞杆菌（Bacillus cereus） ATCC 14579菌株CcpA缺失突变体的转录组数据，并进行启动子与CcpA蛋白的体外结合验证，明确Bt HD73菌株中Sigma54和CcpA共同调控的基因，丰富了对微生物的代谢调控网络的认识。[方法]以转录组测序结果为基础，通过基因同源性的比对在Bt HD73菌株中寻找受Sigma54和CcpA共同调控的基因，在这些基因中找到具有cre序列的启动子，通过凝胶阻滞验证这些启动子与CcpA蛋白的结合。[结果]Bt HD73菌株中有31个基因受Sigma54和CcpA共同调控，其中14个基因的启动子序列包含cre序列，这些启动子都可以与CcpA蛋白发生体外结合。[结论]Bt HD73菌株中有14个基因直接受CcpA的调控，同时其转录受Sigma54的控制。

关键词:苏云金芽胞杆菌;Sigma54;CcpA;转录调控

Abstract:

[Objective] We analyzed the Sigma54 mutant regulon data of Bacillus thuringiensis (Bt) HD73 strain and CcpA mutant regulon data of Bacillus cereus ATCC 14579 strain, and verified the binding of promoter and CcpA protein, to determine Sigma54 and CcpA co-regulated genes in Bt HD73 and enrich the understanding of microbial metabolic regulation network. [Methods] Based on the results of transcriptome sequencing, genes regulated by Sigma54 and CcpA were found via the comparison of homology gene in Bt HD73 strain. cre sequence of promoter was found by blast and verified the binding with CcpA protein by electrophoresis mobility shift assays. [Results] Thirty-one genes were co-regulated by Sigma54 and CcpA in Bt HD73 strain. The fourteen promoters of these genes contained the cre sequence, which could bind to the CcpA protein in vitro. [Conclusion] Fourteen genes were directly regulated by CcpA in Bt HD73, while their transcription was controlled by Sigma 54. This finding provides clues to the study of sporulation and crystalformation through the point of view the metabolic regulation, and enriches the Bt metabolic regulation network.

Key words:Bacillus thuringiensis;Sigma54;CcpA;transcriptional regulation