Role of PhoP∼P in Transcriptional Regulation of Genes Involved in Cell Wall Anionic Polymer Biosynthesis in Bacillus subtilis

tagA, tagD, and tuaA operons are responsible for the synthesis of cell wall anionic polymer, teichoic acid, and teichuronic acid, respectively, in Bacillus subtilis. Under phosphate starvation conditions, teichuronic acid is synthesized while teichoic acid synthesis is inhibited. Expression of these genes is controlled by PhoP-PhoR, a two-component system. It has been proposed that Pho-P plays a key role in the activation of tuaA and the repression of tagA and tagD. In this study, we demonstrated the role of Pho-P in the switch process from teichoic acid synthesis to teichuronic acid synthesis, by using an in vitro transcription system. The results indicate that PhoP approximately P is sufficient to repress the transcription of the tagA and tagD promoters and also to activate the transcription of the tuaA promoter.