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Biofilm formation in Escherichia coli cra mutants is impaired due to down-regulation of curli biosynthesis

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Title Biofilm formation in Escherichia coli cra mutants is impaired due to down-regulation of curli biosynthesis
 
Creator RESHAMWALA, SMS
NORONHA, SB
 
Subject SIGNAL-TRANSDUCTION PATHWAY
SALMONELLA-TYPHIMURIUM
GENE-EXPRESSION
TRANSCRIPTION FACTORS
FIBRONECTIN-BINDING
IN-VITRO
PSEUDOMONAS-AERUGINOSA
CATABOLITE REPRESSION
EXTRACELLULAR-MATRIX
GLOBAL REGULATOR
Cra
Curli
Biofilm
Consensus sequence
 
Description Cra is a pleiotropic regulatory protein that controls carbon and energy flux in enteric bacteria. Recent studies have shown that Cra also regulates other cell processes and influences biofilm formation. The purpose of the present study was to investigate the role of Cra in biofilm formation in Escherichia coli. Congo red-binding studies suggested that curli biosynthesis is impaired in cra mutants. Microarray analysis of wild-type and mutant E. coli cultivated in conditions promoting biofilm formation revealed that the curli biosynthesis genes, csgBAC and csgDEFG, are poorly expressed in the mutant, suggesting that transcription of genes required for curli production is regulated by Cra. Four putative Cra-binding sites were identified in the curli intergenic region, which were experimentally validated by performing electromobility shift assays. Site-directed mutagenesis of three Cra-binding sites in the promoter region of the csgDEFG operon suggests that Cra activates transcription of this operon upon binding to operator regions both downstream and upstream of the transcription start site. Based on the Cra-binding sites identified in this and other studies, the Cra consensus sequence is refined.
 
Publisher SPRINGER
 
Date 2012-06-26T05:12:51Z
2012-06-26T05:12:51Z
2011
 
Type Article
 
Identifier ARCHIVES OF MICROBIOLOGY,193(10)711-722
0302-8933
http://dx.doi.org/10.1007/s00203-011-0708-7
http://dspace.library.iitb.ac.in/jspui/handle/100/13938
 
Language English