A lymphoid cell-specific nuclear factor containing c-Rel-like proteins preferentially interacts with interleukin-6 kappa B-related motifs whose activities are repressed in lymphoid cells.
The proto-oncoprotein c-Rel is a member of the nuclear factor kappa B transcription factor family, which includes the p50 and p65 subunits of nuclear factor kappa B. We show here that c-Rel binds to kappa B sites as homodimers as well as heterodimers with p50. These homodimers and heterodimers show distinct DNA-binding specificities and affinities for various kappa B motifs. In particular, the c-Rel homodimer has a high affinity for interleukin-6 (IL-6) and beta interferon kappa B sites. In spite of its association with p50 in vitro, however, we found a lymphoid cell-specific nuclear factor in vivo that contains c-Rel but not p50 epitopes; this factor, termed IL-6 kappa B binding factor II, appears to contain the c-Rel homodimer and preferentially recognizes several IL-6 kappa B-related kappa B motifs. Although it has been previously shown that the IL-6 kappa B motif functions as a potent IL-1/tumor necrosis factor-responsive element in nonlymphoid cells, its activity was found to be repressed in lymphoid cells such as a Jurkat T-cell line. We also present evidence that IL-6 kappa B binding factor II functions as a repressor specific for IL-6 kappa B-related kappa B motifs in lymphoid cells.
Department of Molecular Pathology, Kanazawa University, Ishikawa, Japan.
K
K
Nakayama
H
H
Shimizu
K
K
Mitomo
T
T
Watanabe
S
S
Okamoto
K
K
Yamamoto
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology; D000939:Epitopes; D005786:Gene Expression Regulation; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics; D046911:Macromolecular Substances; D008957:Models, Genetic; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D020569:Proto-Oncogene Proteins c-rel; D012689:Sequence Homology, Nucleic Acid; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D014018:Tissue Distribution; D014157:Transcription Factors / Q000378:metabolism*
D016207:Cytokines; D000939:Epitopes; D015850:Interleukin-6; D046911:Macromolecular Substances; D011518:Proto-Oncogene Proteins; D020569:Proto-Oncogene Proteins c-rel; D014157:Transcription Factors