I kappa B alpha-mediated inhibition of v-Rel DNA binding requires direct interaction with the RXXRXRXXC Rel/kappa B DNA-binding motif.
Rel family proteins bind to kappa B DNA sites, form heterodimers with one another, and modulate expression of genes linked to kappa B motifs. I kappa B factors associate with Rel proteins, inhibit Rel DNA binding in vitro, and displace DNA from DNA-bound Rel complexes. We have investigated the mechanism by which the p40/I kappa B alpha inhibitor interfers with Rel DNA-binding activity. Here, we report that p40 contacts the RXXRXRXXC DNA-binding motif conserved in all Rel family proteins, in addition to associating with the nuclear localizing sequence. Competition assays with a Rel-derived peptide comprising the DNA-binding region specifically alleviated p40-mediated inhibition of v-Rel DNA-binding activity, whereas a covalently modified Rel peptide was inactive. Combined, these results indicate that I kappa B alpha interaction with the RXXRXRXXC motif is required for inhibition of v-Rel DNA binding and suggest that nuclear I kappa B factors may be critical for regulating transcription by Rel family proteins.
Kumar
S
S
Center for Advanced Biotechnology and Medicine, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway 08854-5638.
Gélinas
C
C
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D002522:Chlorocebus aethiops; D004247:DNA / Q000378:metabolism*; D007668:Kidney; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000378:metabolism; D020572:Oncogene Proteins v-rel; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D015682:Retroviridae Proteins, Oncogenic / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion; D014162:Transfection
D009838:Oligodeoxyribonucleotides; D020572:Oncogene Proteins v-rel; D010455:Peptides; D015682:Retroviridae Proteins, Oncogenic; D004247:DNA; D015500:Chloramphenicol O-Acetyltransferase; D011505:Protein-Tyrosine Kinases