SigmaK和GerE对芽胞外壁基质结构基因exsB的转录调控

摘要

[目的]明确SigmaK和GerE对苏云金芽胞杆菌(Bacillus thuringiensis,简称Bt)芽胞外壁(exosporium)基质结构基因exsB的转录调控.[方法]序列比较蜡样芽胞杆菌群exsB及启动区序列,利用启动子融合lacZ技术检测exsB启动子的转录活性；通过凝胶阻滞方法检测GerE与exsB启动子的结合.[结果]在蜡样芽胞杆菌群中,exsB及其启动区具有较高的相似性,exsB启动子在芽胞形成期的晚期大量转录；sigK和gerE的突变影响了exsB启动子的转录活性,凝胶阻滞结果显示GerE蛋白与exsB启动子可以结合.[结论]本研究证明exsB在芽胞形成晚期受到SigmaK转录调控,并直接受到GerE的正调控.%[Objective] To identify the transcriptional regulation of exosporium basal layer structural gene exsB in Bacillus thuringiensis.[Methods] We analyzed exsB and its promoter sequence in Bacillus cereus group by sequence alignment.We performed beta-galactosidase assay of exsB-lacZ gene fusion to analyze transcriptional activation of exsB promoter; we used Electrophoretic mobility shift assays to detect binding of GerE and exsB promoter.[Results] exsB was the high similarity in Bacillus cereus group strains.Beta-galactosidase assay showed that exsB promoter had the strong transcriptional activation on the late sporulation phase.Deletion of gerE or sigK gene decreased the activation of exsB promoter.Electrophoretic mobility shift assays showed that GerE could bind with exsB promoter.[Conclusion] The exsB gene is regulated by SigmaK and GerE on the late sporulation phase.