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PMID:22843849
| Citation |
Allison, SE, Silphaduang, U, Mascarenhas, M, Konczy, P, Quan, Q, Karmali, M and Coombes, BK (2012) Novel repressor of Escherichia coli O157:H7 motility encoded in the putative fimbrial cluster OI-1. J. Bacteriol. 194:5343-52 |
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| Abstract |
Escherichia coli O157:H7 is a gastrointestinal pathogen that has become a serious public health concern, as it is associated with outbreaks and severe diseases such as hemolytic-uremic syndrome. The molecular basis of its greater virulence than that of other serotypes is not completely known. OI-1 is a putative fimbria-encoding genomic island that is found almost exclusively in O157:H7 Shiga toxin-producing E. coli strains and may be associated with the enhanced pathogenesis of these strains. In this study, we identified and characterized a novel repressor of flagellar synthesis encoded by OI-1. We showed that deletion of Z0021 increased the motility of E. coli O157:H7, which correlated with an increase in flagellin production and enhanced assembly of flagella on the cell surface. In contrast, overexpression of Z0021 inhibited motility. We demonstrated that Z0021 exerted its regulatory effects downstream of the transcription and translation of flhDC but prior to the activation of class II/III promoters. Furthermore, the master regulator of flagellar synthesis, FlhD(4)C(2), was shown to be a high-copy suppressor of the nonmotile phenotype associated with elevated levels of Z0021--a finding consistent with Z0021-FlhD(4)C(2) being a potential regulatory complex. This work provides insight into the mechanism by which Z0021, which we have named fmrA, represses flagellar synthesis and is the first report of a fimbrial-operon-encoded inhibitor of motility in E. coli O157:H7. |
| Links |
PubMed PMC3457194 Online version:10.1128/JB.01025-12 |
| Keywords |
Amino Acid Sequence; Escherichia coli O157/genetics; Escherichia coli O157/metabolism; Fimbriae Proteins/genetics; Fimbriae Proteins/metabolism; Flagella/physiology; Gene Deletion; Gene Expression Regulation, Bacterial/physiology; Genomic Islands; Molecular Sequence Data; Movement; Multigene Family/genetics; Plasmids/physiology; Promoter Regions, Genetic; Transcription, Genetic; Virulence |
| edit table |
Significance
Annotations
| Gene product | Qualifier | GO Term | Evidence Code | with/from | Aspect | Extension | Notes | Status |
|---|---|---|---|---|---|---|---|---|
| GO:1902201: negative regulation of bacterial-type flagellum-dependent cell motility |
|
P |
Seeded From UniProt |
complete | ||||
| GO:1902201: negative regulation of bacterial-type flagellum-dependent cell motility |
ECO:0000315: mutant phenotype evidence used in manual assertion |
P |
Figure 2 shows that mutant strains without the Z0020 gene have increased swimming motility and Figure 3 shows this is due to increased flagellum production. |
complete | ||||
Notes
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