Analysis of Bordetella pertussis virulence gene regulation by use of transcriptional fusions in Escherichia coli.
The virulence regulon of Bordetella pertussis includes a trans-acting regulatory locus, bvg, that is required for expression of several virulence factors. The virulence control system also responds to environmental signals. We have reconstructed a bvg-dependent regulatory system in Escherichia coli by using bacteriophage lambda vectors carrying transcriptional fusions to lacZYA. Single-copy lacZYA fusions to the B. pertussis fhaB locus, which encodes the attachment factor filamentous hemagglutinin, were activated nearly 400-fold by pBR322 replicons carrying sequences that included bvg. In contrast, bvg had no effect on the pertussis toxin operon (ptxA-E) promoter in E. coli as measured by ptxA-lacZ expression. Environmental signals that modulate expression of virulence genes in B. pertussis had a pronounced effect on bvg-mediated activation of fhaB-lacZ. MgSO4, nicotinic acid, and low temperature resulted in decreases in beta-galactosidase activities of 175-, 115-, and 45-fold respectively. Sensory transduction and transcriptional activation were tightly coupled, and both required an intact bvg locus as determined by 5' and 3' deletions that eliminated both activities.
Miller
J F
JF
Department of Microbiology and Immunology, Stanford University, California 94305.
Roy
C R
CR
Falkow
S
S
D001886:Bordetella pertussis / Q000235:genetics* / Q000472:pathogenicity; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005838:Genotype; D010957:Plasmids; D015183:Restriction Mapping; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic; D014774:Virulence / Q000235:genetics
D014157:Transcription Factors