Stimulation of the phage lambda pL promoter by integration host factor requires the carboxy terminus of the alpha-subunit of RNA polymerase.
Escherichia coli integration host factor (IHF) binds with high affinity to two tandem IHF consensus sequences located upstream from the pL promoter of bacteriophage lambda. IHF was shown to stimulate transcription initiation from the pL promoter by increasing close complex formation (KB). We show here, by the use of reconstituted mutant RNA polymerases, that the C-terminal portion of the alpha subunit of RNA polymerase plays an essential role in the stimulation of transcription by IHF. Our results are in agreement with the hypothesis that IHF, like the cAMP-CRP activator, increases the affinity of RNA polymerase to the promoter by protein-protein interaction.
Giladi
H
H
Department of Molecular Genetics, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Igarashi
K
K
Ishihama
A
A
Oppenheim
A B
AB
D001426:Bacterial Proteins / Q000378:metabolism*; D010582:Bacteriophage lambda / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D034982:Integration Host Factors; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D034982:Integration Host Factors; D012321:DNA-Directed RNA Polymerases