title: Regulation of the response regulator gene degU through the binding of SinR/SlrR and exclusion of SinR/SlrR by DegU in Bacillus subtilis.
abstract: Bacillus subtilis DegU is a response regulator of the DegS-DegU two-component regulatory system. Phosphorylated DegU (DegU-P) controls many genes and biological processes, such as exoprotease and γ-polyglutamic acid production, in addition to the degU gene, by binding to target gene promoters. Nonphosphorylated DegU and low levels of DegU-P are required for swarming motility and genetic competence. The DNA-binding repressors SinR and SlrR are part of a double-negative feedback loop and comprise the epigenetic switch governing biofilm formation. In this study, we found that SinR repressed degU. Furthermore, SlrR, which interacts with SinR through protein-protein interaction, seems to have an active role in degU expression in in vivo lacZ analysis. An in vitro transcription assay supported this observation. An electrophoretic mobility shift assay (EMSA) showed that SinR bound to the degU promoter and that SlrR formed a complex with SinR on the degU promoter. In EMSA, DegU-P excluded the SinR/SlrR complex but not SinR from the degU promoter in the presence of RNA polymerase. These findings suggest that DegU-P interacts with SlrR. In support of this hypothesis, disruption of the slrR gene resulted in decreased degU expression. This newly identified regulatory mechanism for degU is considered to be sequential transcription factor replacement.
authors: Institute of Oceanic Research and Development, Tokai University, Shizuoka, Japan.
authors: Mitsuo
authors: M
authors: Ogura
authors: Hirofumi
authors: H
authors: Yoshikawa
authors: Taku
authors: T
authors: Chibazakura
mesh_terms: D019677:Artificial Gene Fusion; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D012097:Repressor Proteins / Q000378:metabolism*; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C066497:DegU protein, Bacteria; D012097:Repressor Proteins; C076733:FlaD protein, Bacteria; D001616:beta-Galactosidase