Linked Life Data

2553535

Source:http://linkedlifedata.com/resource/pubmed/id/2553535

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1989-12-12
pubmed:abstractText
The integration host factor (IHF) binds to a site (ihf) that overlaps the -35 region of the phage lambda late rightward promoter (p'R). This interaction represses p'R-promoted transcription, both in vivo and in vitro. In vivo repression was observed when a plasmid carrying both p'R and the galK reporter gene was transfected into IHF+ or IHF- hosts. In vitro repression of transcription by IHF was observed only with linear, but not with supercoiled wild-type p'R templates. When binding to ihf, IHF imposes a strong bend on the DNA and protects this site from cleavage by neocarzinostatin, pancreatic DNase I, and hydroxyl radicals, as assessed by footprinting experiments. Both the functional and nonfunctional p'R mutants, in which the upstream part of the -35 region was replaced by an EcoRI linker, show modified behavior toward IHF. Some are more sensitive to IHF-mediated repression, even in the supercoiled form, while others have lost their affinity for IHF. We conclude that IHF binding depends not only on the consensus ihf sequence, but also on a suitable combination of the sequences of both ihf and neighboring regions, together with the DNA conformation, which includes both natural and imposed bends in DNA and the degree of supercoiling. Based on most of the present data, it is difficult to predict the relationship between the ihf sequence and IHF interaction, since two very different sequences (less than 50% homology) show strong IHF binding, whereas very similar sequences (80-87% homology) show a very different behavior. However, the hydroxylradical footprinting data show that three A + T-rich sequences are protected by IHF: the central sequence, which overlaps the -35 region of p'R, and two flanking sequences removed by one helix turn. All three sequences are located on the same face of the helix, and the amino acid side chains of IHF seem to occupy the narrow minor groove. A novel consensus sequence is proposed.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0378-1119
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
81
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1-15
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:2553535-Bacterial Proteins, pubmed-meshheading:2553535-Bacteriophage lambda, pubmed-meshheading:2553535-Base Sequence, pubmed-meshheading:2553535-DNA, Superhelical, pubmed-meshheading:2553535-DNA, Viral, pubmed-meshheading:2553535-DNA-Binding Proteins, pubmed-meshheading:2553535-Deoxyribonuclease I, pubmed-meshheading:2553535-Escherichia coli, pubmed-meshheading:2553535-Galactokinase, pubmed-meshheading:2553535-Genes, Viral, pubmed-meshheading:2553535-Hydroxides, pubmed-meshheading:2553535-Hydroxyl Radical, pubmed-meshheading:2553535-Integration Host Factors, pubmed-meshheading:2553535-Molecular Sequence Data, pubmed-meshheading:2553535-Mutation, pubmed-meshheading:2553535-Nucleic Acid Conformation, pubmed-meshheading:2553535-Promoter Regions, Genetic, pubmed-meshheading:2553535-Transcription, Genetic
pubmed:year
1989
pubmed:articleTitle
Physical and biological consequences of interactions between integration host factor (IHF) and coliphage lambda late p'R promoter and its mutants.
pubmed:affiliation
McArdle Laboratory for Cancer Research, University of Wisconsin, Madison 53706.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.