Motility of Helicobacter pylori is coordinately regulated by the transcriptional activator FlgR, an NtrC homolog.
sigma54 is the subunit of bacterial RNA polymerase that transcribes from promoters with enhancer elements bound by enhancer-binding proteins. By computer searches of Helicobacter pylori genomic sequences, chromosomal gene disruption, and RNA analyses, we have identified sigma54-recognized promoters that regulate transcription of flagellar basal body and hook genes, as well as the enhancer-binding protein FlgR (flagellum regulator), a transactivating protein of the NtrC family. We demonstrate that FlgR is required for bacterial motility and transcription of five promoters for seven basal body and hook genes. In addition, FlgR acts as a repressor of transcription of the sigma28-regulated flaA flagellin gene promoter, while changes in DNA topology repress transcription of the sigma54-regulated flaB flagellin gene promoter. Our data indicate that regulation of flagellar gene expression in H. pylori shows similarities with that in enterobacteriaceae and Caulobacter.
Spohn
G
G
Department of Molecular Biology, Chiron SpA, 53100 Siena, Italy.
Scarlato
V
V
D001426:Bacterial Proteins; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D005407:Flagella / Q000235:genetics / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D016480:Helicobacter pylori / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009068:Movement; D016296:Mutagenesis; D016366:Open Reading Frames; D051922:PII Nitrogen Regulatory Proteins; D011401:Promoter Regions, Genetic; D051877:RNA Polymerase Sigma 54; D015183:Restriction Mapping; D012808:Sigma Factor / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D051922:PII Nitrogen Regulatory Proteins; D012808:Sigma Factor; D015534:Trans-Activators; D014157:Transcription Factors; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54