Characterization of the Bacillus subtilis YxdJ response regulator as the inducer of expression for the cognate ABC transporter YxdLM

Abstract

The genome ofBacillus subtilis, like those of some other AT-rich Gram-positive bacteria, has the uncommon feature of containing several copies of arrangements in which the genes encoding two-component and cognate ABC transporter systems are adjacent. As the function of one of these systems, the product of theyxdlocus, is still unknown, it was analysed further in order to get some clues on the physiological role of the gene products it encodes. TheyxdJgene was shown to encode a DNA-binding protein that directly controls transcription of the neighbouring operon encoding the ABC transporter YxdLM. Primer extension and DNase protection experiments allowed precise definition of theyxdLMtranscription start and controlling region. Two putative direct repeats were identified that are proposed to be the YxdJ response regulator binding sites. Whole-cell transcriptome analyses revealed that the YxdJ regulon is extremely restricted. In addition to theyxdJKLMyxeAoperon, only a few genes involved in modifications of the bacterial cell wall were shown to be regulated by YxdJ.