Analysis of the V antigen lcrGVH-yopBD operon of Yersinia pseudotuberculosis: evidence for a regulatory role of LcrH and LcrV

• Published in: Journal of Bacteriology Vol. 173; no. 5; pp. 1607 - 1616
• Main Authors: Bergman, T. (University of Umea, Umea, Sweden), Hakansson, S, Forsberg, A, Norlander, L, Macellaro, A, Backman, A, Bolin, I, Wolf-Watz, H
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01-03-1991
• Subjects: ADN; Amino Acid Sequence; ANTIGENE; ANTIGENOS; Antigens, Bacterial - genetics; ARN MENSAJERO; ARN MESSAGER; Bacteriology; Base Sequence; Biological and medical sciences; Calcium - pharmacology; Cloning, Molecular; DNA, Bacterial - genetics; DNA, Bacterial - isolation & purification; EXPRESION GENICA; EXPRESSION DES GENES; Fundamental and applied biological sciences. Psychology; Genes, Bacterial; Genes, Regulator; GENETICA; GENETIQUE; Microbiology; Models, Biological; Molecular Sequence Data; MUTANT; MUTANTES; NUCLEOTIDE; NUCLEOTIDOS; Operon; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; PLASMIDE; PLASMIDIOS; Plasmids; PODER PATOGENO; Polymerase Chain Reaction; Pore Forming Cytotoxic Proteins; POUVOIR PATHOGENE; Promoter Regions, Genetic; Restriction Mapping; RNA, Bacterial - genetics; RNA, Bacterial - isolation & purification; SECUENCIA NUCLEICA; SEQUENCE NUCLEIQUE; Transcription, Genetic; Virulence - genetics; Yersinia - drug effects; Yersinia - genetics; Yersinia - pathogenicity; YERSINIA PSEUDOTUBERCULOSIS; Genome organization; Nucleotide sequence; Transcription; Operon; Virulence; V antigen; Gene expression; Regulation(control); Gene; Bacteria; Aminoacid sequence; Enterobacteriaceae; Yersinia pseudotuberculosis
• ISSN: 0021-9193; 1098-5530; 1067-8832
• DOI: 10.1128/jb.173.5.1607-1616.1991

Virulent Yersinia species possess a common plasmid that encodes essential virulence determinants (Yops) which are regulated by the extracellular stimuli Ca2+ and temperature. The V antigen operon was recently shown to be involved in the Ca2+ -regulated negative pathway (A. Forsberg and H. Wolf-Watz, Mol. Microbiol. 2:121-133, 1988). We show here that the V antigen-containing operon of Yersinia pseudotuberculosis is a polycistronic operon having the gene order lcrGVH-yopBD. DNA sequencing analysis of lcrGVH revealed a high homology to the corresponding genes of Yersinia pestis. LcrG was conserved and LcrH showed only one amino acid difference, while LcrV showed only 96.6% identity. The amino acid substitutions of LcrV occurred in the central domain of the protein, while the two ends of the protein were conserved. Northern (RNA) blotting experiments showed that the operon is regulated at the transcriptional level by the extracellular stimuli temperature and calcium. One 4.6-kb transcriptional product of the operon was identified. This mRNA is rapidly processed at its 5' end, resulting in different mRNA species of variable stability. By genetic analysis, the lcrV and lcrH gene products were found to be regulatory proteins having important roles in the Ca2+ -controlled regulation of Yop expression. The activity of LcrH is modulated by a gene product of the operon that inhibits the negative action of LcrH on yop transcription in the absence of Ca2+