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Differential regulation of fasA and fasH expression of Escherichia coli 987P fimbriae by environmental cues
Author(s) -
Edwards Robert A.,
Schifferli Dieter M.
Publication year - 1997
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1997.5161875.x
Subject(s) - biology , enterotoxigenic escherichia coli , fimbria , microbiology and biotechnology , escherichia coli , vibrio cholerae , gene expression , pilus , bacteria , gene , biochemistry , genetics , enterotoxin
An early process in the pathogenesis of enteric bacteria is colonization of the intestinal epithelium leading to local multiplication, pathophysiological interactions with the host and further spreading. Attachment is typically mediated by bacterial fimbriae, which are selectively expressed during growth in the intestine. Here we report an analysis of the regulation of 987P fimbrial expression of enterotoxigenic Escherichia coli (ETEC). Expression of both fasH , the transcriptional activator of the 987P fimbrial genes, and fasA , the major fimbrial subunit, is regulated in response to a variety of environmental stimuli. We have found that expression of fasH is regulated in response to the carbon status of the growth medium by the cAMP–CRP complex. Moreover, fasH is regulated in response to both the nitrogen status of the growth medium and the external pH. Expression of fasA is activated by FasH, and is also selectively regulated in response to growth temperature by HNS. Regulation of fimbrial expression by carbon and/or nitrogen gradients is proposed to provide a mechanism that allows preferential colonization of different segments of the intestine by various enteropathogens, such as ETEC, enteropathogenic E . coli and Vibrio cholerae .