Yersinia pestis, the causative agent of plague, contains a virulence plasmid pCD that encodes an adaptive mechanism called the low-Ca2+ response. This mechanism confers upon the bacteria the ability to use the environmental cues of temperature, Ca2+ and nucleotides to regulate growth and the expression of two proteins known as the plague virulence antigens V and M. The low-Ca2+ response is thought to ensure that virulence functions such as B and M are expressed in the proper environment within the mammalian host. Genetic studies have shown that a large region on pCD contains genes necessary for expression of the low-Ca2+ response, and 5 low-Ca2+ response (lcr) genes have been identified. Five other pCD genes are strongly regulated in their expression by Ca2+, nucleotides, and temperature. These are candidates for virulence functions regulated in the low-Ca2+ response.
The specific aims of this project are to determine the identities, genetic arrangement, and functional relation of lcr genes to each other and to the pCD genes that are regulated by Ca2+ and nucleotides, using molecular genetic manipulations and mutagenesis techniques. The products of these genes will be identified with the aid of protein fusions to beta-galactosidase, specific antibody, and two-dimensional electrophoresis. The molecular basis of regulation of gene expression by Ca2+ and nucleotides will be probed by obtaining and characterizing mutant Y. pestis aberrant in these properties. The role of pCD gene products in pathogenesis will be studied by kinetically characterizing the fates of parent and mutant strains of Y. pestis in mouse peritoneal cavities and determining the classes of mammalian cells that are involved in the interactions. These studies have the long-range goal of understanding the molecular basis of the low-Ca2+ response and of the function of pCD genes in pathogenesis of a severe infectious disease. They also will enhance our understanding of regulatory mechanisms in enteric bacteria, since the regulation of bacterial growth by Ca2+ and nucleotides is novel.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI021017-04
Application #
3130912
Study Section
Bacteriology and Mycology Subcommittee 1 (BM)
Project Start
1983-09-01
Project End
1989-08-31
Budget Start
1986-12-01
Budget End
1987-11-30
Support Year
4
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Kentucky
Department
Type
Schools of Medicine
DUNS #
832127323
City
Lexington
State
KY
Country
United States
Zip Code
40506
Fowler, Janet M; Wulff, Christine R; Straley, Susan C et al. (2009) Growth of calcium-blind mutants of Yersinia pestis at 37 degrees C in permissive Ca2+-deficient environments. Microbiology 155:2509-21
Cowan, Clarissa; Philipovskiy, Alexander V; Wulff-Strobel, Christine R et al. (2005) Anti-LcrV antibody inhibits delivery of Yops by Yersinia pestis KIM5 by directly promoting phagocytosis. Infect Immun 73:6127-37
Wulff-Strobel, Christine R; Williams, Andrew W; Straley, Susan C (2002) LcrQ and SycH function together at the Ysc type III secretion system in Yersinia pestis to impose a hierarchy of secretion. Mol Microbiol 43:411-23
Cowan, C; Jones, H A; Kaya, Y H et al. (2000) Invasion of epithelial cells by Yersinia pestis: evidence for a Y. pestis-specific invasin. Infect Immun 68:4523-30
Fields, K A; Straley, S C (1999) LcrV of Yersinia pestis enters infected eukaryotic cells by a virulence plasmid-independent mechanism. Infect Immun 67:4801-13
Payne, P L; Straley, S C (1999) YscP of Yersinia pestis is a secreted component of the Yop secretion system. J Bacteriol 181:2852-62
Fields, K A; Nilles, M L; Cowan, C et al. (1999) Virulence role of V antigen of Yersinia pestis at the bacterial surface. Infect Immun 67:5395-408
Payne, P L; Straley, S C (1998) YscO of Yersinia pestis is a mobile core component of the Yop secretion system. J Bacteriol 180:3882-90
Williams, A W; Straley, S C (1998) YopD of Yersinia pestis plays a role in negative regulation of the low-calcium response in addition to its role in translocation of Yops. J Bacteriol 180:350-8
Nilles, M L; Fields, K A; Straley, S C (1998) The V antigen of Yersinia pestis regulates Yop vectorial targeting as well as Yop secretion through effects on YopB and LcrG. J Bacteriol 180:3410-20

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