双组份系统YvcPQ抑制苏云金芽胞杆菌的芽胞形成

Regulation of sporulation by two-component system YvcPQ in Bacillus thuringiensis

【目的】探究双组份系统YvcPQ影响芽胞形成的机制。【方法】利用β-半乳糖苷酶活性实验验证YvcP对芽胞形成抑制因子KapD的调控作用;通过无痕基因敲除并分别比较突变株与出发菌株的芽胞产率,研究YvcPQ及KapD对芽胞形成的影响;应用细菌单杂交实验、EMSA实验和实时荧光定量PCR技术探究转录调控因子AbrB对yvcPQ操纵子的转录调节。【结果】YvcP可以正调控kapD的表达,从而抑制芽胞形成;yvcPQ不能受YvcP的自调控,而是受AbrB转录激活。【结论】调控因子AbrB能够通过正调控yvcPQ操纵子的转录来提高细胞内YvcP的含量,进而增强YvcP对芽胞形成抑制因子编码基因kapD的表达,最终抑制芽胞的形成。

[Objective] To study the regulation of sporulation controlled by two-component system（TCS） YvcPQ. [Methods] β-galactosidase experiment was used to verify the regulation of YvcP on kap D expression; bacterial one-hybrid assay, EMSA and RT-qPCR were applied to study the regulation of AbrB on yvcPQ expression; markerless gene deletion coupled with spore count was used to reveal the influence of yvcPQ and kapD expressions on sporulation. [Results] The transcriptional regulator Abr B up-regulated the expression of yvcPQ; YvcP promoted the expression of kapD to inhibit sporulation. [Conclusion] AbrB up-regulated the transcription of yvcPQ operon, then the increased YvcP strengthened the transcriptional acitivation of sporulation inhibitor gene kapD, and subsequently inhibited sporulation.