Faculty Opinions recommendation of Novel regulators of the csgD gene encoding the master regulator of biofilm formation in Escherichia coli K-12.

Under stressful conditions, Escherichia coli forms biofilm for survival by sensing a variety of environmental conditions. CsgD, the master regulator of biofilm formation, controls cell aggregation by directly regulating the synthesis of Curli fimbriae. In agreement of its regulatory role, as many as 14 transcription factors (TFs) have so far been identified to participate in regulation of the csgD promoter, each monitoring a specific environmental condition or factor. In order to identify the whole set of TFs involved in this typical multi-factor promoter, we performed in this study ‘promoter-specific transcription-factor’ (PS-TF) screening in vitro using a set of 198 purified TFs (145 TFs with known functions and 53 hitherto uncharacterized TFs). A total of 48 TFs with strong binding to the csgD promoter probe were identified, including 35 known TFs and 13 uncharacterized TFs, referred to as Y-TFs. As an attempt to search for novel regulators, in this study we first analysed a total of seven Y-TFs, including YbiH, YdcI, YhjC, YiaJ, YiaU, YjgJ and YjiR. After analysis of curli fimbriae formation, LacZ-reporter assay, Northern-blot analysis and biofilm formation assay, we identified at least two novel regulators, repressor YiaJ (renamed PlaR) and activator YhjC (renamed RcdB), of the csgD promoter.

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Regulatory role of pyruvate-sensing BtsSR in biofilm formation by Escherichia coli K-12

FEMS Microbiology Letters ◽

10.1093/femsle/fnz251 ◽

2019 ◽

Vol 366 (24) ◽

Cited By ~ 2

Author(s):

Hiroshi Ogasawara ◽

Toshiyuki Ishizuka ◽

Kotaro Yamaji ◽

Yuki Kato ◽

Tomohiro Shimada ◽

...

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Target Genes ◽

Gene Encoding ◽

Regulatory Pathways ◽

High Affinity ◽

Gene Sets ◽

Component Systems ◽

Two Component Systems ◽

K 12

ABSTRACT Pyruvate, the key regulator in connection of a variety of metabolic pathways, influences transcription of the Escherichia coli genome through controlling the activity of two pyruvate-sensing two-component systems (TCSs), BtsSR and PyrSR. Previously, we identified the whole set of regulatory targets of PyrSR with low-affinity to pyruvate. Using gSELEX screening system, we found here that BtsSR with high-affinity to pyruvate regulates more than 100 genes including as many as 13 transcription factors genes including the csgD gene encoding the master regulator of biofilm formation. CsgD regulates more than 20 target genes including the csg operons encoding the Curli fimbriae. In addition, we identified the csgBAC as one of the regulatory targets of BtsR, thus indicating the involvement of two pyruvate-dependent regulatory pathways of the curli formation: indirect regulation by CsgD; and direct regulation by BtsR. Based on the findings of the whole set of regulatory targets by two pyruvate-sensing BtsR and PyrR, we further propose an innovative concept that the pyruvate level-dependent regulation of different gene sets takes place through two pyruvate-sensing TCS systems, high-affinity BtsSR and low-affinity PyrSR to pyruvate.

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YdgG (TqsA) Controls Biofilm Formation in Escherichia coli K-12 through Autoinducer 2 Transport

Journal of Bacteriology ◽

10.1128/jb.188.2.587-598.2006 ◽

2006 ◽

Vol 188 (2) ◽

pp. 587-598 ◽

Cited By ~ 128

Author(s):

Moshe Herzberg ◽

Ian K. Kaye ◽

Wolfgang Peti ◽

Thomas K. Wood

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Acid Production ◽

Polysialic Acid ◽

Fold Increase ◽

Uncharacterized Protein ◽

Biofilm Thickness ◽

Autoinducer 2 ◽

Membrane Spanning ◽

K 12

ABSTRACT YdgG is an uncharacterized protein that is induced in Escherichia coli biofilms. Here it is shown that deletion of ydgG decreased extracellular and increased intracellular concentrations of autoinducer 2 (AI-2); hence, YdgG enhances transport of AI-2. Consistent with this hypothesis, deletion of ydgG resulted in a 7,000-fold increase in biofilm thickness and 574-fold increase in biomass in flow cells. Also consistent with the hypothesis, deletion of ydgG increased cell motility by increasing transcription of flagellar genes (genes induced by AI-2). By expressing ydgG in trans, the wild-type phenotypes for extracellular AI-2 activity, motility, and biofilm formation were restored. YdgG is also predicted to be a membrane-spanning protein that is conserved in many bacteria, and it influences resistance to several antimicrobials, including crystal violet and streptomycin (this phenotype could also be complemented). Deletion of ydgG also caused 31% of the bacterial chromosome to be differentially expressed in biofilms, as expected, since AI-2 controls hundreds of genes. YdgG was found to negatively modulate expression of flagellum- and motility-related genes, as well as other known products essential for biofilm formation, including operons for type 1 fimbriae, autotransporter protein Ag43, curli production, colanic acid production, and production of polysaccharide adhesin. Eighty genes not previously related to biofilm formation were also identified, including those that encode transport proteins (yihN and yihP), polysialic acid production (gutM and gutQ), CP4-57 prophage functions (yfjR and alpA), methionine biosynthesis (metR), biotin and thiamine biosynthesis (bioF and thiDFH), anaerobic metabolism (focB, hyfACDR, ttdA, and fumB), and proteins with unknown function (ybfG, yceO, yjhQ, and yjbE); 10 of these genes were verified through mutation to decrease biofilm formation by 40% or more (yfjR, bioF, yccW, yjbE, yceO, ttdA, fumB, yjiP, gutQ, and yihR). Hence, it appears YdgG controls the transport of the quorum-sensing signal AI-2, and so we suggest the gene name tqsA.

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Bioinformatic and Molecular Analysis of Inverse Autotransporters from Escherichia coli

mSphere ◽

10.1128/msphere.00572-19 ◽

2019 ◽

Vol 4 (4) ◽

Cited By ~ 3

Author(s):

Kelvin G. K. Goh ◽

Danilo G. Moriel ◽

Steven J. Hancock ◽

Minh-Duy Phan ◽

Mark A. Schembri

Keyword(s):

Escherichia Coli ◽

Cell Surface ◽

Biofilm Formation ◽

Secretion System ◽

Content Type ◽

E Coli ◽

Wide Range ◽

Type V Secretion ◽

K 12 ◽

Type V

ABSTRACT Proteins secreted by the type V secretion system possess multiple functions, including the capacity to mediate adhesion, aggregation, and biolfilm formation. The type V secretion system can be divided into five subclasses, one of which is the type Ve system. Proteins of the type Ve secretion system are also referred to as inverse autotransporters (IATs). In this study, we performed an in silico analysis of 126 completely sequenced Escherichia coli genomes available in the NCBI database and identified several distinct IAT-encoding gene families whose distribution varied throughout the E. coli phylogeny. The genes included three characterized IATs (intimin, fdeC, and yeeJ) and four uncharacterized IATs (here named iatA, iatB, iatC, and iatD). The four iat genes were cloned from the completely sequenced environmental E. coli strain SMS-3-5 and characterized. Three of these IAT proteins (IatB, IatC, and IatD) were expressed at the cell surface and possessed the capacity to mediate biofilm formation in a recombinant E. coli K-12 strain. Further analysis of the iatB gene, which showed a unique association with extraintestinal E. coli strains, suggested that its regulation is controlled by the LeuO global regulator. Overall, this study provides new data describing the prevalence, sequence variation, domain structure, function, and regulation of IATs found in E. coli. IMPORTANCE Escherichia coli is one of the most prevalent facultative anaerobes of the human gut. E. coli normally exists as a harmless commensal but can also cause disease following the acquisition of genes that enhance its pathogenicity. Adhesion is an important first step in colonization of the host and is mediated by an array of cell surface components. In E. coli, these include a family of adhesins secreted by the type V secretion system. Here, we identified and characterized new proteins from an emerging subclass of the type V secretion system known as the inverse autotransporters (IATs). We found that IAT-encoding genes are present in a wide range of strains and showed that three novel IATs were localized on the E. coli cell surface and mediated biofilm formation. Overall, this study provides new insight into the prevalence, function, and regulation of IATs in E. coli.

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Regulatory role of MlrA in transcription activation of csgD, the master regulator of biofilm formation in Escherichia coli

FEMS Microbiology Letters ◽

10.1111/j.1574-6968.2010.02112.x ◽

2010 ◽

Vol 312 (2) ◽

pp. 160-168 ◽

Cited By ~ 43

Author(s):

Hiroshi Ogasawara ◽

Kaneyoshi Yamamoto ◽

Akira Ishihama

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Transcription Activation ◽

Regulatory Role ◽

Master Regulator

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Nickel Promotes Biofilm Formation by Escherichia coli K-12 Strains That Produce Curli

Applied and Environmental Microbiology ◽

10.1128/aem.02171-08 ◽

2009 ◽

Vol 75 (6) ◽

pp. 1723-1733 ◽

Cited By ~ 40

Author(s):

Claire Perrin ◽

Romain Briandet ◽

Gregory Jubelin ◽

Philippe Lejeune ◽

Marie-Andrée Mandrand-Berthelot ◽

...

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Molecular Mechanisms ◽

Selective Advantage ◽

Bacterial Survival ◽

Toxic Compounds ◽

E Coli ◽

Transcriptional Effect ◽

K 12 ◽

Encoding Genes

ABSTRACT The survival of bacteria exposed to toxic compounds is a multifactorial phenomenon, involving well-known molecular mechanisms of resistance but also less-well-understood mechanisms of tolerance that need to be clarified. In particular, the contribution of biofilm formation to survival in the presence of toxic compounds, such as nickel, was investigated in this study. We found that a subinhibitory concentration of nickel leads Escherichia coli bacteria to change their lifestyle, developing biofilm structures rather than growing as free-floating cells. Interestingly, whereas nickel and magnesium both alter the global cell surface charge, only nickel promotes biofilm formation in our system. Genetic evidence indicates that biofilm formation induced by nickel is mediated by the transcriptional induction of the adhesive curli-encoding genes. Biofilm formation induced by nickel does not rely on efflux mechanisms using the RcnA pump, as these require a higher concentration of nickel to be activated. Our results demonstrate that the nickel-induced biofilm formation in E. coli is an adaptational process, occurring through a transcriptional effect on genes coding for adherence structures. The biofilm lifestyle is obviously a selective advantage in the presence of nickel, but the means by which it improves bacterial survival needs to be investigated.

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