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
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Creator |
RESHAMWALA, SMS
NORONHA, SB |
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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 |
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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.
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Publisher |
SPRINGER
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Date |
2012-06-26T05:12:51Z
2012-06-26T05:12:51Z 2011 |
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Type |
Article
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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 |
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Language |
English
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