Linked Life Data

11737635

Source:http://linkedlifedata.com/resource/pubmed/id/11737635

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2001-12-12
pubmed:abstractText
Truncated derivatives of the Escherichia coli nucleoid-associated protein H-NS that lack the DNA-binding domain remain competent for silencing of the cryptic bgl operon in vivo. Previous studies have provided evidence for the involvement of either the homologous nucleoid protein StpA or the alternative sigma factor RpoS in this unusual silencing mechanism. Here, we rationalize this apparent discrepancy. We show that two hns alleles (hns-205::Tn10 and hns60), which produce virtually identical amino-terminal fragments of H-NS, have very different requirements for StpA to mediate bgl silencing. The hns60 allele produces a high level of truncated H-NS, which can overcome the absence of StpA, whereas the lower level expressed by hns-205::Tn10 requires StpA for silencing. Reversing the relative levels of the two H-NS fragments reverses their requirement for StpA to silence bgl transcription. This suggests that the amino-terminal fragment of H-NS can be targeted to DNA to mediate silencing by multiple protein-protein interactions. The high-specificity interaction with StpA can function at low levels of truncated H-NS, whereas an alternative mechanism, perhaps involving lower specificity interactions with another protein(s), is only functional when truncated H-NS is abundant. These findings have important implications for the involvement of other proteins in H-NS-dependent transcriptional repression.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
903-17
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Requirement for the molecular adapter function of StpA at the Escherichia coli bgl promoter depends upon the level of truncated H-NS protein.
pubmed:affiliation
Institute of Cell and Molecular Biology, University of Edinburgh, The King's Buildings, Mayfield Road, Edinburgh EH9 3JR, UK. Andrew.Free@ed.ac.uk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't