Identification of a C/EBP-Rel complex in avian lymphoid cells.
Protein-protein interactions between the CCAAT box enhancer-binding proteins (C/EBP) and the Rel family of transcription factors have been implicated in the regulation of cytokine gene expression. We have used sequence-specific DNA affinity chromatography to purify a complex from avian T cells that binds to a consensus C/EBP motif. Our results provide evidence that Rel-related proteins are components of the C/EBP-DNA complex as a result of protein-protein interactions with the C/EBP proteins. A polyclonal antiserum raised against the Rel homology domain of v-Rel and antisera raised against two human RelA-derived peptides specifically induced a supershift of the C/EBP-DNA complex in mobility shift assays using the affinity-purified C/EBP. In addition, several kappa B-binding proteins copurified with the avian C/EBP complex through two rounds of sequence-specific DNA affinity chromatography. The kappa B-binding proteins are distinct from the C/EBP proteins that directly contact DNA containing the C/EBP binding site. The identification of a protein complex that binds specifically to a consensus C/EBP site and contains both C/EBP and Rel family members suggests a novel mechanism for regulation of gene expression by Rel family proteins.
Diehl
J A
JA
Biochemistry Department, University of Missouri, Columbia 65212.
Hannink
M
M
D000818:Animals; D001483:Base Sequence; D001717:Birds; D022762:CCAAT-Enhancer-Binding Proteins; D002846:Chromatography, Affinity; D016384:Consensus Sequence; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics; D008221:Lymphoid Tissue / Q000166:cytology / Q000378:metabolism*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism*; D020572:Oncogene Proteins v-rel; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D015682:Retroviridae Proteins, Oncogenic / Q000302:isolation & purification / Q000378:metabolism*; D014157:Transcription Factors / Q000302:isolation & purification / Q000378:metabolism*
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D015850:Interleukin-6; D046911:Macromolecular Substances; D016328:NF-kappa B; D009687:Nuclear Proteins; D020572:Oncogene Proteins v-rel; D015682:Retroviridae Proteins, Oncogenic; D014157:Transcription Factors