Identification of a Bordetella pertussis regulatory factor required for transcription of the pertussis toxin operon in Escherichia coli.
Transcription of the pertussis toxin operon (ptx) is positively regulated in Bordetella pertussis by the bvgAS locus. However, a ptx-lacZ transcriptional fusion in Escherichia coli cannot be activated by bvgAS in trans. This suggests that an additional factor(s) is required for transcription of ptx. A gene encoding a Bvg accessory factor (Baf) was identified by its ability to activate an E. coli ptx-lacZ fusion in the presence of bvgAS. The expression of ptx-lacZ was decreased by the addition of 40 mM MgSO4, a compound that also modulates ptx expression in B. pertussis. Baf alone did not activate expression of an E. coli fhaB-lacZ fusion, nor did it increase expression of fhaB-lacZ in trans with bvgAS. The gene encoding Baf was localized, sequenced, and found to produce a novel 28-kDa protein. Sequences homologous to B. pertussis baf were identified in Bordetella bronchiseptica and Bordetella parapertussis but not in Bordetella avium. When an additional copy of baf was integrated into the chromosome of BC75, a B. pertussis mutant that produces a low level of pertussis toxin, pertussis toxin production was partially complemented in the cointegrate strain.
DeShazer
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Department of Microbiology and Immunology, University of Arizona, Tucson 85724, USA.
Wood
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GE
Friedman
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RL
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D015139:Blotting, Southern; D015153:Blotting, Western; D001886:Bordetella pertussis / Q000235:genetics* / Q000472:pathogenicity; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D008957:Models, Genetic; D008969:Molecular Sequence Data; D037342:Pertussis Toxin; D014176:Protein Biosynthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D010566:Virulence Factors, Bordetella / Q000096:biosynthesis*
D001426:Bacterial Proteins; C094422:Bvg accessory factor protein, Bordetella pertussis; C065601:BvgA protein, Bacteria; D029968:Escherichia coli Proteins; C489314:EvgA protein, E coli; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D010566:Virulence Factors, Bordetella; C080662:bvgS protein, Bordetella pertussis; D037342:Pertussis Toxin