Type 4 piliated bacteria are involved in a variety of ophthalmic and other disease. Bacteria known to express type 4 pili include Moraxella bovis, Neisseria gonorrhoeae, Bacteroides nodosus, Pseudomonas aeruginosa and Vibrio cholerae. Type 4 pili are related both in terms of amino-terminal amino acid sequence homology and antibody cross-reactivities, and also functionally since cloning just the pilin genes of B. NOdosus or M. bovis into P. aeruginosa allow expression of B. nodosus or M. bovis pili. The goal of this project is to understand the genetics and molecular biology of type 4 pili, particularly those on bacteria of the genera Moraxella and Kingella. M. bovis and M. lacunata pilin gene expression is regulated by the inversion of a 2 kb region of DNA, which in M. bovis Epp63 results in the expression of either Q or I pili. We plan to further investigate the mechanisms of this pilin gene inversion event, and ultimately to carry out the inversion event in an in vitro system of completely define components. Sequence analysis of polymerase chain reaction (PCR) amplified DNA from nonpiliated (P-) variants will be used to determine the mechanisms of P+ to P- switch for M. bovis and M. lacunata. We have identified an open reading frame (ORF1) whose role is as yet unknown, but it seems to be coexpressed with Q (but not I) pilin. We plan transcriptional studies to localize the pilin gene promoter, to determine whether ORF1 is coexpressed with Q-pilin, and then to isolate the protein coded for by ORF1 and determine if it is a minor structural component of the pilus, or if it has other roles in pilus biosynthesis. Genomic Southern hybridization analysis of Kingella denitrificans reveals multiple DNA fragments which hybridize to the Q-pilin gene probe. This appears similar to the hybridization patterns seen in the multi-pilin gene system of N. gonorrhoeae, and we plan to clone, analyze and map the pilin gene loci of K. denitrificans to determine if they are organized and undergo antigenic variation similar to that described for N. gonorrhoeae.

National Institute of Health (NIH)
National Eye Institute (NEI)
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Bacteriology and Mycology Subcommittee 2 (BM)
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University of Michigan Ann Arbor
Public Health & Prev Medicine
Schools of Public Health
Ann Arbor
United States
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Weir, S; Lee, L W; Marrs, C F (1997) Type-4 pili of Kingella denitrificans. Gene 192:171-6
Weir, S; Lee, L W; Marrs, C F (1996) Identification of four complete type 4 pilin genes in a single Kingella denitrificans genome. Infect Immun 64:4993-9
Ruehl, W W; Marrs, C; Beard, M K et al. (1993) Q pili enhance the attachment of Moraxella bovis to bovine corneas in vitro. Mol Microbiol 7:285-8
Weir, S; Marrs, C F (1992) Identification of type 4 pili in Kingella denitrificans. Infect Immun 60:3437-41
Tonjum, T; Marrs, C F; Rozsa, F et al. (1991) The type 4 pilin of Moraxella nonliquefaciens exhibits unique similarities with the pilins of Neisseria gonorrhoeae and Dichelobacter (Bacteroides) nodosus. J Gen Microbiol 137:2483-90
Patel, P; Marrs, C F; Mattick, J S et al. (1991) Shared antigenicity and immunogenicity of type 4 pilins expressed by Pseudomonas aeruginosa, Moraxella bovis, Neisseria gonorrhoaea, Dichelobacter nodosus, and Vibrio cholerae. Infect Immun 59:4674-6
Rozsa, F W; Marrs, C F (1991) Interesting sequence differences between the pilin gene inversion regions of Moraxella lacunata ATCC 17956 and Moraxella bovis Epp63. J Bacteriol 173:4000-6
Marrs, C F; Rozsa, F W; Hackel, M et al. (1990) Identification, cloning, and sequencing of piv, a new gene involved in inverting the pilin genes of Moraxella lacunata. J Bacteriol 172:4370-7
Marrs, C F; Weir, S (1990) Pili (fimbriae) of Branhamella species. Am J Med 88:36S-40S
Beard, M K; Mattick, J S; Moore, L J et al. (1990) Morphogenetic expression of Moraxella bovis fimbriae (pili) in Pseudomonas aeruginosa. J Bacteriol 172:2601-7

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