A carbon starvation survival gene of Pseudomonas putida is regulated by sigma 54.
By using mini-Tn5 transposon mutagenesis, two mutants of Pseudomonas putida ATCC 12633 were isolated which showed a marked increase in their sensitivity to carbon starvation; these mutants are presumably affected in the Pex type of proteins that P. putida induces upon carbon starvation (M. Givskov, L. Eberl, and S. Molin, J. Bacteriol. 176:4816-4824, 1994). The affected genes in our mutants were induced about threefold upon carbon starvation. The promoter region of the starvation gene in the mutant MK107 possessed a strong sigma 54-type-promoter sequence, and deletion analysis suggested that this was the major promoter regulating expression; this was confirmed by transcript mapping in rpoN+ and rpoN mutant backgrounds. The deletion analysis implicated a sequence upstream of the sigma 54 promoter, as well as a region downstream of the transcription start site, in the functioning of the promoter. Two sigma 70-type Pribnow boxes were also detected in the promoter region, but their transcriptional activity in the wild type was very weak. However, in a sigma 54-deficient background, these promoters became stronger. The mechanism and possible physiological role of this phenomenon and the possibility that the sequence upstream of the sigma 54 promoter may have a role in carbon sensing are discussed.
Kim
Y
Y
Department of Microbiology and Immunology, Stanford University School of Medicine, California 94305-5402.
Watrud
L S
LS
Matin
A
A
D001483:Base Sequence; D002244:Carbon / Q000378:metabolism*; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D016958:Pseudomonas putida / Q000235:genetics* / Q000378:metabolism; D051877:RNA Polymerase Sigma 54; D012808:Sigma Factor / Q000235:genetics / Q000502:physiology*; D014241:Trichloroethylene / Q000378:metabolism
D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D012808:Sigma Factor; D014241:Trichloroethylene; D002244:Carbon; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54