A novel complex between the p65 subunit of NF-kappa B and c-Rel binds to a DNA element involved in the phorbol ester induction of the human urokinase gene

EMBO J. 1992 Jan;11(1):205-13.


The NF-kappa B subunits, p50 and p65, have extensive sequence homology with the c-rel proto-oncogene and the Drosophila morphogen dorsal. It has recently been shown that in vitro translated c-Rel can bind to DNA and form a complex with p50. However, the conditions for DNA binding of c-Rel in vivo and its DNA sequence specificity have not been established. Here we report the identification a novel heterodimeric complex that binds to a kappa B-like, phorbol ester (TPA) responsive DNA sequence, 5'-GGGAAAGTAC-3', in the 5' flanking region of the human urokinase (uPA) gene. This sequence was shown to bind two protein complexes, LC and UC. LC was indistinguishable from NF-kappa B as it reacted with antibodies recognizing the p50 subunit of NF-kappa B, and was shown by UV crosslinking to contain the p50 and p65 subunits of NF-kappa B. UC, on the other hand, strongly reacted with anti-v-Rel, but not with the anti-p50 antibodies, and was shown by crosslinking to contain 75 kDa and 85 kDa protein-DNA adducts. The 75 kDa and the 85 kDa adducts could be immunoprecipitated only by anti-p65 and anti-c-Rel antibodies, respectively, showing that c-Rel formed a heterodimer with p65. Both protein complexes were present in inactive forms in HeLa cell cytosol, and their nuclear translocation was induced by TPA. DNA binding of UC and LC could, furthermore, be inhibited by I kappa B-alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Line
  • DNA-Binding Proteins / genetics
  • Gene Expression Regulation / drug effects*
  • Humans
  • Macromolecular Substances
  • Molecular Sequence Data
  • NF-kappa B / genetics*
  • Phorbol Esters / pharmacology*
  • Protein-Tyrosine Kinases / genetics
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / immunology
  • Proto-Oncogene Proteins c-rel
  • Regulatory Sequences, Nucleic Acid / genetics*
  • Sequence Homology, Nucleic Acid
  • Urokinase-Type Plasminogen Activator / genetics*


  • DNA-Binding Proteins
  • Macromolecular Substances
  • NF-kappa B
  • Phorbol Esters
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-rel
  • Protein-Tyrosine Kinases
  • Urokinase-Type Plasminogen Activator