Transcriptional control of toxT, a regulatory gene in the ToxR regulon of Vibrio cholerae.
Co-ordinate expression of many virulence genes in Vibrio cholerae is under the control of the ToxR and ToxT proteins. These proteins function in a regulatory cascade in which ToxR is required to activate toxT, and ToxT activates virulence genes. The precise mechanism for ToxR activation of toxT is unknown, but data presented in this report suggest a direct involvement of ToxR. Primer extension and gene fusion analyses identified a ToxR-regulated promoter directly upstream of toxT, immediately following a region of inverted repeats capable of terminating transcription. Gel mobility shift studies indicate that ToxR binds DNA within the inverted repeat region, yet preliminary evidence suggests that ToxR binding alone is not sufficient for activation of toxT. Possible mechanisms of ToxR-dependent toxT expression are discussed.
Higgins
D E
DE
Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor 48109.
DiRita
V J
VJ
D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites; D002876:Chromosomes, Bacterial; D003001:Cloning, Molecular; D017931:DNA Primers; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D004926:Escherichia coli; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D007438:Introns; D008969:Molecular Sequence Data; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000096:biosynthesis; D018085:Regulon; D012091:Repetitive Sequences, Nucleic Acid; D014157:Transcription Factors / Q000096:biosynthesis*; D014158:Transcription, Genetic; D014734:Vibrio cholerae / Q000235:genetics* / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics; D001616:beta-Galactosidase / Q000096:biosynthesis
D001426:Bacterial Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; C499324:toxR protein, Vibrio cholerae; C066719:toxR protein, bacteria; C075626:tcpN protein, Vibrio cholerae; D001616:beta-Galactosidase