Affiliation:
1. Department of Microbiology and Immunology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157-1064.
Abstract
Expression of type 1 fimbriae in Escherichia coli K-12 is phase variable and associated with the inversion of a short DNA element (switch). The fim switch requires either fimB (on-to-off or off-to-on switching) or fimE (on-to-off switching only) and is affected by the global regulators leucine-responsive regulatory protein (Lrp), integration host factor (IHF), and H-NS. Here it is shown that switching frequencies are regulated by both temperature and media and that these effects appear to be independent. fimE-promoted on-to-off switching occurs far more rapidly than previously estimated (0.3 per cell per generation in defined rich medium at 37 degrees C) and faster at lower than at higher temperatures. In direct contrast, fimB-promoted switching increases with temperature, with optima between 37 and 41 degrees C. Switching promoted by both fimB and fimE is stimulated by aliphatic amino acids (alanine, isoleucine, leucine, and valine), and this stimulation requires lrp. Furthermore, lrp appears to differentially regulate fimB- and fimE-promoted switching in different media.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Reference46 articles.
1. An invertible element of DNA controls phase variation of type 1 fimbriae of Escherichia coli;Abraham J. M.;Proc. Natl. Acad. Sci. USA,1985
2. Fimbrial phase variation and DNA rearrangements in uropathogenic isolates of Escherichia coli;Abraham J. M.;Mol. Biol. Med.,1986
3. Impaired colonization by and full invasiveness of Escherichia coli Kl bearing a sitedirected mutation in the type 1 pilin gene;Bloch C. A.;Infect. Immun.,1990
4. Lrp stimulates phase variation of type 1 fimbriation in Escherichia coli K-12;Blomifteld I. C.;J. Bacteriol.,1993
5. Blomfield I. C. and B. I. Eisenstein. Unpublished data.
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