Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID:Differential regulation of fasA and fasH expression of Escherichia coli 987P fimbriae by environmental cues. 937 7

Adaptation to the changing environment requires both the integration of external signals and the co-ordination of internal responses. Around 50 non-coding small RNAs (sRNAs) have been described in Escherichia coli; the levels of many of these vary with changing environmental conditions. This suggests that they play a role in cell adaptation. In this review, we use the regulation of RpoS (sigma38) translation as a paradigm of sRNA-mediated response to environmental conditions; rpoS is currently the only known gene regulated post-transcriptionally by at least three sRNAs. DsrA and RprA stimulate RpoS translation in response to low temperature and cell surface stress, respectively, whereas OxyS represses RpoS translation in response to oxidative shock. However, in addition to regulating RpoS translation, DsrA represses the translation of HNS (a global regulator of gene expression), whereas OxyS represses the translation of FhlA (a transcriptional activator), allowing the cell to co-ordinate different pathways involved in cell adaptation. Environmental cues affect the synthesis and stability of specific sRNAs, resulting in specific sRNA-dependent translational control.
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PMID:Small non-coding RNAs, co-ordinators of adaptation processes in Escherichia coli: the RpoS paradigm. 1275 81

The bacterial Rcs phosphorelay signals perturbations of the bacterial cell envelope to its response regulator RcsB, which regulates transcription of multiple loci related to motility, biofilm formation and various stress responses. RcsB is unique, as its set of target loci is modulated by interaction with auxiliary regulators including BglJ. The BglJ-RcsB heteromer is known to activate the HNS repressed leuO and bgl loci independent of RcsB phosphorylation. Here, we show that BglJ-RcsB activates the promoters of 10 additional loci (chiA, molR, sfsB, yecT, yqhG, ygiZ, yidL, ykiA, ynbA and ynjI). Furthermore, we mapped the BglJ-RcsB binding site at seven loci and propose a consensus sequence motif. The data suggest that activation by BglJ-RcsB is DNA phasing dependent at some loci, a feature reminiscent of canonical transcriptional activators, while at other loci BglJ-RcsB activation may be indirect by inhibition of HNS-mediated repression. In addition, we show that BglJ-RcsB activates transcription of bgl synergistically with CRP where it shifts the transcription start by 20 bp from a position typical for class I CRP-dependent promoters to a position typical for class II CRP-dependent promoters. Thus, BglJ-RcsB is a pleiotropic transcriptional activator that coordinates regulation with global regulators including CRP, LeuO and HNS.
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PMID:Transcriptional regulation by BglJ-RcsB, a pleiotropic heteromeric activator in Escherichia coli. 2433 84