The transcriptional activator HlyU of Vibrio cholerae: nucleotide sequence and role in virulence gene expression.
HlyU upregulates expression of the haemolysin, HlyA, of Vibrio cholerae. DNA sequence analysis indicates that HlyU is an 11.9 kDa protein containing a putative helix-turn-helix motif and belonging to a family of small regulatory proteins, including NoIR (Rhizobium meliloti), SmtB (Synechococcus PCC 7942) and ArsR (plasmids R773, Escherichia coli; pI258, Staphylococcus aureus; and pSX267, Staphylococcus xylosus). An hlyU mutant was constructed by insertional inactivation, and found to be deficient in the production of both the haemolysin and a 28 kDa secreted protein. The mutant was assessed for virulence in the infant mouse cholera model, revealing a 100-fold increase in the LD50. This suggests that HlyU promotes expression of virulence determinant(s) in vivo.
Williams
S G
SG
Department of Microbiology and Immunology, University of Adelaide, South Australia.
Attridge
S R
SR
Manning
P A
PA
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins; D001483:Base Sequence; D002771:Cholera / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D018257:Helix-Loop-Helix Motifs / Q000235:genetics; D006460:Hemolysin Proteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014734:Vibrio cholerae / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D014774:Virulence
D001426:Bacterial Proteins; D006460:Hemolysin Proteins; D014157:Transcription Factors; C084287:hlyA protein, Vibrio cholerae; C084286:hlyU protein, Vibrio cholerae