DNA binding and I kappa B inhibition of the cloned p65 subunit of NF-kappa B, a rel-related polypeptide

Cell. 1991 Mar 8;64(5):961-9. doi: 10.1016/0092-8674(91)90320-x.


The sequence and biochemical properties of the product of the cloned cDNA for the p65 subunit of nuclear factor kappa B (NF-kappa B) have been determined. The cDNA has an open reading frame of 549 amino acids capable of encoding a 60 kd protein. NF-kappa B p65 contains an amino-terminal region of 320 amino acids with extensive similarity to the oncogene c-rel and lesser similarity to NF-kappa B p50. In vitro translated p65 forms a DNA-binding complex with NF-kappa B p50, and the binding of this complex can be specifically inhibited by purified I kappa B. Progressive carboxy-terminal deletions of p65 show that, contrary to previous assumptions, p65 does include a DNA-binding domain that in vivo might become activated only through hetero-oligomerization with p50. DNA binding by truncated p65 is inhibited by I kappa B, thus mapping the I kappa B interaction domain to the rel-homologous region and suggesting that I kappa B exerts its inhibitory effect upon NF-kappa B primarily through interaction with p65.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • Macromolecular Substances
  • Mice
  • Models, Structural
  • Molecular Sequence Data
  • NF-kappa B / genetics
  • NF-kappa B / isolation & purification
  • NF-kappa B / metabolism*
  • Oligonucleotide Probes
  • Open Reading Frames
  • Polymerase Chain Reaction
  • Protein Binding
  • Protein Biosynthesis
  • Protein Conformation
  • Protein-Tyrosine Kinases / metabolism
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-rel
  • Rabbits
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Repressor Proteins / isolation & purification
  • Repressor Proteins / pharmacology*
  • Restriction Mapping
  • Sequence Homology, Nucleic Acid


  • Macromolecular Substances
  • NF-kappa B
  • Oligonucleotide Probes
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-rel
  • Recombinant Proteins
  • Repressor Proteins
  • Protein-Tyrosine Kinases

Associated data

  • GENBANK/M59201
  • GENBANK/M61909
  • GENBANK/M63698
  • GENBANK/M63700
  • GENBANK/M63702
  • GENBANK/M63718
  • GENBANK/S63145
  • GENBANK/S63146
  • GENBANK/S63147
  • GENBANK/S63148