The pathogenicity of Vibrio cholerae, which infects mucosal surfaces in the small intestine, is believed to be a coordinated and multifactorial process. Unfortunately, knowledge of which genes are expressed during infection, as well as the regulatory proteins and host signals that govern their regulation, is rudimentary. A novel gene reporter system has been constructed for identifying in vivo induced genes of V. cholerae, and has been used to identify the vie (V. cholerae in vivo expressed) operon. vie is predicted to encode three two-component signal transduction proteins, including a sensor and two response regulators, the first such system described in V. cholerae. vie is unique among such systems both in its operon structure and its exclusive expression during infection. Based on analogy to other systems, it is hypothesized that the Vie proteins function by sensing environmental conditions in the host intestine and responding by regulating other genes. Characterization of vie thus provides a unique opportunity both to probe the host signals and bacterial regulatory proteins that control V. cholerae growth and pathogenicity as well as to allow investigation of vie-regulated genes. The goals of this research proposal are to characterize the vie operon and to identify and characterize vie-regulated genes. Mutations will be constructed in both vie and vie-regulated genes, and the effects of each on pathogenicity will be measured. The subcellular locations of the Vie proteins will be determined using immunochemical methods. The spatial and temporal expression patterns of the vie operon and vie-regulated genes will be determined during infection. This work may contribute to development of mucosal vaccines and to identification of new targets for therapies against mucosal pathogens.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
First Independent Research Support & Transition (FIRST) Awards (R29)
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Bacteriology and Mycology Subcommittee 2 (BM)
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Tufts University
Schools of Medicine
United States
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Li, Caiyi C; Merrell, D Scott; Camilli, Andrew et al. (2002) ToxR interferes with CRP-dependent transcriptional activation of ompT in Vibrio cholerae. Mol Microbiol 43:1577-89
Merrell, D Scott; Camilli, Andrew (2002) Acid tolerance of gastrointestinal pathogens. Curr Opin Microbiol 5:51-5
Tischler, Anna D; Lee, Sang Ho; Camilli, Andrew (2002) The Vibrio cholerae vieSAB locus encodes a pathway contributing to cholera toxin production. J Bacteriol 184:4104-13
Merrell, D Scott; Hava, David L; Camilli, Andrew (2002) Identification of novel factors involved in colonization and acid tolerance of Vibrio cholerae. Mol Microbiol 43:1471-91
Hava, D L; Camilli, A (2001) Isolation and characterization of a temperature-sensitive generalized transducing bacteriophage for Vibrio cholerae. J Microbiol Methods 46:217-25
Lee, S H; Butler, S M; Camilli, A (2001) Selection for in vivo regulators of bacterial virulence. Proc Natl Acad Sci U S A 98:6889-94
Merrell, D S; Bailey, C; Kaper, J B et al. (2001) The ToxR-mediated organic acid tolerance response of Vibrio cholerae requires OmpU. J Bacteriol 183:2746-54
Merrell, D S; Camilli, A (2000) Regulation of vibrio cholerae genes required for acid tolerance by a member of the ""ToxR-like"" family of transcriptional regulators. J Bacteriol 182:5342-50
Slauch, J M; Camilli, A (2000) IVET and RIVET: use of gene fusions to identify bacterial virulence factors specifically induced in host tissues. Methods Enzymol 326:73-96
Merrell, D S; Tischler, A D; Lee, S H et al. (2000) Vibrio cholerae requires rpoS for efficient intestinal colonization. Infect Immun 68:6691-6

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