CCAAT/enhancer binding protein alpha (C/EBP alpha) undifferentiated protein: a developmentally regulated nuclear protein that binds to the C/EBP alpha gene promoter.
During differentiation of 3T3-L1 preadipocytes into adipocytes, transcription of the C/EBP alpha (CCA-AT/enhancer binding protein alpha) gene is activated. The promoter of the C/EBP alpha gene contains a bipartite cis element with binding sites for C/EBP alpha undifferentiated protein (CUP) and an Sp1-like GT box binding protein. Binding of CUP to this element is markedly enhanced by its interaction with the Sp1-like protein. CUP, purified approximately 100,000-fold from HeLa cell nuclear extracts, appears to be composed of at least two types of subunit. Evidence is presented that a CUP-containing protein complex bridges between the CUP/Sp1-like GT box element and a downstream cis element, which contains a C/EBP binding site. During differentiation of 3T3-L1 preadipocytes into adipocytes, CUP activity or expression decreases as expression of C/EBP alpha increases. It is suggested that bridging by the CUP-containing protein complex may play a role in transcriptional regulation of the C/EBP alpha gene.
Vasseur-Cognet
M
M
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Lane
M D
MD
D016475:3T3 Cells; D000273:Adipose Tissue / Q000166:cytology*; D000818:Animals; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D002454:Cell Differentiation; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D011401:Promoter Regions, Genetic; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000378:metabolism*
D022762:CCAAT-Enhancer-Binding Proteins; C082509:CUP protein, human; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; C493668:Tfap2a protein, mouse; D050656:Transcription Factor AP-2; D014157:Transcription Factors