Previous Article | Next Article ![]()
J. Bacteriol., May 1995, 2530-2542, Vol 177, No. 9
E Skrzypek and SC Straley
The Yersinia pestis V antigen is necessary for full induction of low-
calcium response (LCR) stimulon virulence gene transcription, and it also
is a secreted protein believed to have a direct antihost function. We made
four nonpolar deletions in lcrV of Y. pestis to determine if secretion,
regulation, and virulence functions could be localized within the V antigen
(LcrV). Deletion of amino acids 25 to 40 caused secretion of LcrV to be
decreased in efficiency; however, removal of residues 108 to 125
essentially abolished LcrV secretion. Neither mutation had a significant
effect on LCR regulation. This showed that LcrV does not have to be
secreted to have its regulatory effect and that the internal structure of V
antigen is necessary for its secretion. Both mutants were avirulent in
mice, showing that the regulatory effect of LcrV could be separated
genetically from its virulence role and raising the possibility that
residues 25 to 40 are essential for the virulence function. This study
provides the best genetic evidence available that LcrV per se is necessary
for the virulence of Y. pestis. The repressed LCR phenotype of a mutant
lacking amino acids 188 to 207 of LcrV raised the possibility that the
deleted region is necessary for regulation of LCR induction; however, this
mutant LcrV was weakly expressed and may not have been present in
sufficient amounts to have its regulatory effect. In double mutants
containing this mutant lcrV and also lacking expression of known LCR
negative regulators (LcrG, LcrE, and LcrH), full induction of the LCR
occurred in the absence of functional LcrV, indicating that LcrV promotes
induction not as an activator per se but rather by inhibiting negative
regulators.
Copyright © 1995, American Society for Microbiology
Differential effects of deletions in lcrV on secretion of V antigen, regulation of the low-Ca2+ response, and virulence of Yersinia pestis
Department of Microbiology and Immunology, Albert B. Chandler Medical Center, University of Kentucky, Lexington 40536-0084, USA.
This article has been cited by other articles:
| Appl. Environ. Microbiol. | Infect. Immun. | Eukaryot. Cell |
|---|---|---|
| Mol. Cell. Biol. | J. Virol. | Microbiol. Mol. Biol. Rev. |
| ALL ASM JOURNALS |