Integration host factor binds specifically to sites in the ilvGMEDA operon in Escherichia coli.
Integration host factor (IHF) of Escherichia coli is a histone-like protein that is involved both in site-specific recombination and in regulating the expression of a number of phage and bacterial genes. We have shown previously that transcription of the ilvGMEDA operon in E. coli is greatly reduced in IHF mutants. We report here that IHF specifically protects two sites within the ilvGMEDA promoter-regulatory region against DNase I digestion. These sites are located upstream from the promoter and in the leader region just prior to the sequence that specifies the attenuator. The footprinting experiments and gel retardation assays show that these sites have strong affinity for IHF. These data and results with ilvGMEDA-lac promoter fusions suggest a direct role for IHF in expression of the ilvGMEDA operon.
Tsui
P
P
Department of Biochemistry, State University of New York, Stony Brook 11794-5215.
Freundlich
M
M
D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli; D005798:Genes, Bacterial; D034982:Integration Host Factors; D008969:Molecular Sequence Data; D009154:Mutation; D009876:Operon; D001616:beta-Galactosidase / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D034982:Integration Host Factors; D001616:beta-Galactosidase