Repression of Flagellar Genes in Exponential Phase by CsgD and CpxR, Two Crucial Modulators of Escherichia coli Biofilm Formation

Dudin, Omaya; Geiselmann, Johannes; Ogasawara, Hiroshi; Ishihama, Akira; Lacour, Stéphan

doi:10.1128/jb.00938-13

Cited by 48 publications

(45 citation statements)

References 64 publications

(99 reference statements)

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“…Pronounced motility was observed for Tob1, reduced motility for Fec67, Fec101, No.12, and B‐8638, whereas strains B‐11870 and 80//6 were nonmotile (Figure e). Swimming motility was csgD ‐independent, since csgD deletion mutants of strains Tob1 and No.12 displayed similar swimming behavior as the respective wild types (Figure S1), in contrast to a previous study (Dudin, Geiselmann, Ogasawara, Ishihama, & Lacour, ).…”

Section: Resultscontrasting

confidence: 82%

Alterations of c‐di‐GMP turnover proteins modulate semi‐constitutive rdar biofilm formation in commensal and uropathogenic Escherichia coli

Cimdins

Simm

et al. 2017

MicrobiologyOpen

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Agar plate‐based biofilm of enterobacteria like Escherichia coli is characterized by expression of the extracellular matrix components amyloid curli and cellulose exopolysaccharide, which can be visually enhanced upon addition of the dye Congo Red, resulting in a red, dry, and rough (rdar) colony morphology. Expression of the rdar morphotype depends on the transcriptional regulator CsgD and occurs predominantly at ambient temperature in model strains. In contrast, commensal and pathogenic isolates frequently express the csgD‐dependent rdar morphotype semi‐constitutively, also at human host body temperature. To unravel the molecular basis of temperature‐independent rdar morphotype expression, biofilm components and c‐di‐GMP turnover proteins of seven commensal and uropathogenic E. coli isolates were analyzed. A diversity within the c‐di‐GMP signaling network was uncovered which suggests alteration of activity of the trigger phosphodiesterase YciR to contribute to (up)regulation of csgD expression and consequently semi‐constitutive rdar morphotype development.

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Section: Resultscontrasting

confidence: 82%

Alterations of c‐di‐GMP turnover proteins modulate semi‐constitutive rdar biofilm formation in commensal and uropathogenic Escherichia coli

Cimdins

Simm

et al. 2017

MicrobiologyOpen

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“…CsgD is a transcription factor that positively regulates the csgBAC operon (Zogaj et al, 2003; Dudin et al, 2014). The csgBAC operon encodes the major and minor curli fiber components, CsgA and CsgB, respectively (Hammar et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

The Bacterial Curli System Possesses a Potent and Selective Inhibitor of Amyloid Formation

et al. 2015

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Summary Curli are extracellular functional amyloids that are assembled by enteric bacteria during biofilm formation and host colonization. An efficient secretion system and chaperone network ensures that the major curli fiber subunit, CsgA, does not form intracellular amyloid aggregates. We discovered that the periplasmic protein CsgC was a highly effective inhibitor of CsgA amyloid formation. In the absence of CsgC, CsgA formed toxic intracellular aggregates. In vitro, CsgC inhibited CsgA amyloid formation at substoichiometric concentrations and maintained CsgA in a non-β-sheet rich conformation. Interestingly, CsgC inhibited amyloid assembly of human α-synuclein, but not Aβ42, in vitro. We identified a common D-Q-Φ-X0,1-G-K-N-ζ-E motif in CsgC client proteins that is not found in Aβ42. CsgC is therefore both an efficient and selective amyloid inhibitor. Dedicated functional amyloid inhibitors may be a key feature that distinguishes functional amyloids from disease-associated amyloids.

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“…Dudin et al (19) recently found that CsgD can directly inhibit the transcription of fliA, which encodes the sigma factor ( F ) that directs the expression of the late (class 3) flagellar genes. This might provide a more direct regulatory link between CsgD and motility.…”

Section: Resultsmentioning

confidence: 99%

“…Other sources of the motility defect in the ⌬hns strain involve the biofilm regulator CsgD, which is strongly upregulated in the ⌬hns mutant and which was recently shown to inhibit transcription of the fliA (19) as well as of the fliE and fliF (32) operons. Each of these repressing actions appears significant under some conditions.…”

Section: Discussionmentioning

confidence: 99%

Function of the Histone-Like Protein H-NS in Motility of Escherichia coli: Multiple Regulatory Roles Rather than Direct Action at the Flagellar Motor

Kim

Blair

2015

J Bacteriol

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A number of investigations of Escherichia coli have suggested that the DNA-binding protein H-NS, in addition to its well-known functions in chromosome organization and gene regulation, interacts directly with the flagellar motor to modulate its function. Here, in a study initially aimed at characterizing the H-NS/motor interaction further, we identify problems and limitations in the previous work that substantially weaken the case for a direct H-NS/motor interaction. Null hns mutants are immotile, largely owing to the downregulation of the flagellar master regulators FlhD and FlhC. We, and others, previously reported that an hns mutant remains poorly motile even when FlhDC are expressed constitutively. In the present work, we use better-engineered strains to show that the motility defect in a ⌬hns, FlhDC-constitutive strain is milder than that reported previously and does not point to a direct action of H-NS at the motor. H-NS regulates numerous genes and might influence motility via a number of regulatory molecules besides FlhDC. To examine the sources of the motility defect that persists in an FlhDC-constitutive ⌬hns mutant, we measured transcript levels and overexpression effects of a number of genes in candidate regulatory pathways. The results indicate that H-NS influences motility via multiple regulatory linkages that include, minimally, the messenger molecule cyclic di-GMP, the biofilm regulatory protein CsgD, and the sigma factors S and F . The results are in accordance with the more standard view of H-NS as a regulator of gene expression rather than a direct modulator of flagellar motor performance. IMPORTANCEData from a number of previous studies have been taken to indicate that the nucleoid-organizing protein H-NS influences motility not only by its well-known DNA-based mechanisms but also by binding directly to the flagellar motor to alter function. In this study, H-NS is shown to influence motility through diverse regulatory pathways, but a direct interaction with the motor is not supported. Previous indications of a direct action at the motor appear to be related to the use of nonnull strains and, in some cases, a failure to effectively bypass the requirement for H-NS in the expression of the flagellar regulon. These findings call for a substantially revised interpretation of the literature concerning H-NS and flagellar motility and highlight the importance of H-NS in diverse regulatory processes involved in the motile-sessile transition. H-NS is a small DNA-binding protein that occurs widely in Gram-negative bacteria, where it functions to organize chromosomal DNA and regulate hundreds of genes (1-3). Binding of H-NS to the chromosome is not strictly sequence specific but exhibits a preference for certain motifs (4) and for intrinsically curved regions of DNA (5). While the logic underlying the very wide regulatory action of H-NS is not fully understood, generally speaking, it appears to modulate the expression of genes involved in sensing and responding to changes in the environment (6), ...

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Repression of Flagellar Genes in Exponential Phase by CsgD and CpxR, Two Crucial Modulators of Escherichia coli Biofilm Formation

Cited by 48 publications

References 64 publications

Alterations of c‐di‐GMP turnover proteins modulate semi‐constitutive rdar biofilm formation in commensal and uropathogenic Escherichia coli

Alterations of c‐di‐GMP turnover proteins modulate semi‐constitutive rdar biofilm formation in commensal and uropathogenic Escherichia coli

The Bacterial Curli System Possesses a Potent and Selective Inhibitor of Amyloid Formation

Function of the Histone-Like Protein H-NS in Motility of Escherichia coli: Multiple Regulatory Roles Rather than Direct Action at the Flagellar Motor

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