Open AccessCCAAT/enhancer binding protein alpha (C/EBP alpha) undifferentiated protein: a developmentally regulated nuclear protein that binds to the C/EBP alpha gene promoter.
Author(s) -
Mireille Vasseur-Cognet,
M. Daniel Lane
Publication year - 1993
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.90.15.7312
Subject(s) - ccaat enhancer binding proteins , microbiology and biotechnology , biology , nuclear protein , transcription factor , enhancer , fibroblast activation protein, alpha , alpha (finance) , caat box , g alpha subunit , promoter , dna binding protein , binding protein , binding site , transcription (linguistics) , protein subunit , gene expression , gene , biochemistry , genetics , medicine , construct validity , nursing , linguistics , philosophy , cancer , patient satisfaction
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.