Integration host factor stimulates the phage lambda pL promoter

J Mol Biol. 1990 May 5;213(1):109-21. doi: 10.1016/S0022-2836(05)80124-X.


Escherichia coli integration host factor (IHF) is a small dimeric protein that binds to a specific DNA consensus sequence and produces DNA bending. Transcription from the bacteriophage lambda pL promoter is stimulated three- to fourfold by IHF both in vivo and in vitro. IHF binds with high-affinity to two tandem sites located just upstream from the pL promoter and enhances the formation of RNA polymerase-promoter closed complexes. The rate of isomerization to open complex is not influenced by IHF. IHF may stimulate recognition of pL by one or more of several mechanisms: (1) by bending DNA; (2) by making protein-protein contacts with RNA polymerase; or (3) by occluding a competing promoter upstream from pL.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacterial Proteins / metabolism*
  • Bacteriophage lambda / genetics*
  • Base Sequence
  • DNA, Viral / genetics
  • DNA, Viral / metabolism
  • DNA-Binding Proteins / metabolism*
  • DNA-Directed RNA Polymerases / metabolism
  • Escherichia coli / genetics*
  • Integration Host Factors
  • Kinetics
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Promoter Regions, Genetic*
  • Restriction Mapping
  • Transcription, Genetic


  • Bacterial Proteins
  • DNA, Viral
  • DNA-Binding Proteins
  • Integration Host Factors
  • DNA-Directed RNA Polymerases