Regulation of tcp genes in classical and El Tor strains of Vibrio cholerae O1.
Expression of genes encoding the toxin-co-regulated pilus (TCP) varies between the two biotypes of Vibrio cholerae O1. Sequence analysis of the tcp locus from the classical and El Tor strains has revealed differences in the intergenic regions between tcpI and tcpP, and tcpH and tcpA, which may be involved in regulation. To investigate this possibility, transcription of tcpA, and the predicted upstream promoters for tcpI and tcpP, has been analysed in the classical and El Tor strains using promoter-cat (chloramphenicol acetyltransferase) fusions. Together with primer extension analyses, these studies indicate that the tcpA and tcpP promoters are toxR-dependent and suggest that TcpP may be involved in activation of both the tcpI and tcpP promoters. We conclude that differences in the level of tcpA expression in a classical and an El Tor strain are likely to be due to the effect of sequence variation on the ability of control factors to act on these regulatory regions.
Thomas
S
S
Department of Microbiology and Immunology, University of Adelaide, Australia.
Williams
S G
SG
Manning
P A
PA
D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D036781:Fimbriae Proteins; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D018933:Pili, Sex; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*; D015183:Restriction Mapping; D014157:Transcription Factors / Q000235:genetics; D014734:Vibrio cholerae / Q000235:genetics*
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012097:Repressor Proteins; C097244:TCPP protein, Vibrio cholerae; C085807:TcpA protein, Vibrio cholerae; C097245:TcpI protein, Vibrio cholerae; D014157:Transcription Factors; C499324:toxR protein, Vibrio cholerae; C066719:toxR protein, bacteria; D036781:Fimbriae Proteins