Autoregulation of swrAA and motility in Bacillus subtilis.
We demonstrate that transcription of the gene swrAA, required for swarming migration in Bacillus subtilis, is driven by two promoters: a sigD-dependent promoter and a putative sigA-dependent promoter, which is inactive during growth in liquid Luria-Bertani medium and becomes active in the presence of the phosphorylated form of the response regulator DegU or on semisolid surfaces. Since sigD transcription is enhanced by SwrAA, this finding reveals that swrA expression is controlled by a positive feedback loop. We also demonstrate that the positive action of SwrAA in swimming and swarming motility is prevented in strains carrying a deletion of the two-component system degS-degU and that this effect is independent of swrAA transcription. Therefore, both DegU and SwrAA must be present to achieve full motility in B. subtilis.
Dipartimento di Genetica e Microbiologia A Buzzati-Traverso, Università degli Studi di Pavia, Via Ferrata 1, 27100 Pavia, Italy. cinzia.calvio@unipv.it
Cinzia
C
Calvio
Cecilia
C
Osera
Giuseppe
G
Amati
Alessandro
A
Galizzi
D019677:Artificial Gene Fusion; D001412:Bacillus subtilis / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D008124:Locomotion; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012808:Sigma Factor / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; C066497:DegU protein, Bacteria; D012808:Sigma Factor; D001616:beta-Galactosidase