PMID:15534208
| Citation |
Sohanpal, BK, El-Labany, S, Lahooti, M, Plumbridge, JA and Blomfield, IC (2004) Integrated regulatory responses of fimB to N-acetylneuraminic (sialic) acid and GlcNAc in Escherichia coli K-12. Proc. Natl. Acad. Sci. U.S.A. 101:16322-7 |
|---|---|
| Abstract |
Bacterial-host attachment by means of bacterial adhesins is a key step in host colonization. Phase variation (reversible on-off switching) of the type 1 fimbrial adhesin of Escherichia coli involves a DNA inversion catalyzed by FimB (switching in either direction) or FimE (mainly on-to-off switching). fimB is separated from the divergent yjhATS operon by a large (1.4 kbp) intergenic region. Short ( approximately 28 bp) cis-active elements (regions 1 and 2) close to yjhA stimulate fimB expression and are required for sialic acid (Neu(5)Ac) sensitivity of its expression [El-Labany, S., Sohanpal, B. K., Lahooti, M., Akerman, R. & Blomfield, I. C. (2003) Mol. Microbiol. 49, 1109-1118]. Here, we show that whereas NanR, a sialic acid-response regulator, binds to region 1, NagC, a GlcNAc-6P-responsive protein, binds to region 2 instead. The NanR- and NagC-binding sites lie adjacent to deoxyadenosine methylase (Dam) methylation sites (5'-GATC) that are protected from modification, and the two regulators are shown to be required for methylation protection at regions 1 and 2, respectively. Mutations in nanR and nagC diminish fimB expression, and both fimB expression and FimB recombination are inhibited by GlcNAc (3- and >35-fold, respectively). Sialic acid catabolism generates GlcNAc-6-P, and whereas GlcNAc disrupts methylation protection by NagC alone, Neu(5)Ac inhibits the protection mediated by both NanR and NagC as expected. Type 1 fimbriae are proinflammatory, and host defenses enhance the release of both Neu(5)Ac and GlcNAc by a variety of mechanisms. Inhibition of type 1 fimbriation by these amino sugars may thus help balance the interaction between E. coli and its hosts. |
| Links |
PubMed PMC526197 Online version:10.1073/pnas.0405821101 |
| Keywords |
Acetylglucosamine/pharmacology; Bacterial Adhesion/drug effects; Base Sequence; DNA Methylation; DNA, Bacterial/genetics; DNA-Binding Proteins/genetics; DNA-Binding Proteins/physiology; Escherichia coli/drug effects; Escherichia coli/genetics; Escherichia coli/pathogenicity; Escherichia coli/physiology; Escherichia coli Proteins/genetics; Escherichia coli Proteins/physiology; Gene Expression Regulation, Bacterial/drug effects; Genes, Bacterial/drug effects; Integrases/genetics; Integrases/physiology; Molecular Sequence Data; N-Acetylneuraminic Acid/pharmacology; Recombination, Genetic/drug effects; Repressor Proteins/genetics; Repressor Proteins/physiology; Transcription Factors/genetics; Transcription Factors/physiology |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.