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CCAAT/enhancer binding protein activates the promoter of the serum albumin gene in cultured hepatoma cells

Genes Dev. 1989 Sep;3(9):1314-22. doi: 10.1101/gad.3.9.1314.

Abstract

An expression vector capable of encoding full-length CCAAT/enhancer-binding protein (C/EBP) has been constructed and tested in transient transfection assays for its capacity to activate transcription from the promoter of the serum albumin gene. When tested in cultured hepatoma cells, the C/EBP expression vector achieved potent trans-activation of the albumin promoter. Less substantial activation was observed when the same experiment was conducted using cultured mouse fibroblasts. Expression vectors that encoded defective forms of C/EBP failed to activate the albumin promoter. Moreover, mutated variants of the albumin promoter that lack the C/EBP-binding site failed to be trans-activated. The data are consistent with the interpretation that C/EBP is a bona fide transcription factor. During the course of these experiments it was noted also that C/EBP is more than an order of magnitude less concentrated in cultured hepatoma cells than it is in adult liver cells. Given these findings, we speculate that C/EBP may play a general role in establishing and maintaining the differentiated, nonproliferative state.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Carcinoma, Hepatocellular / pathology
  • DNA-Binding Proteins / metabolism*
  • Enhancer Elements, Genetic*
  • Gene Expression Regulation
  • Humans
  • L Cells
  • Liver Neoplasms / pathology
  • Mice
  • Promoter Regions, Genetic*
  • Rats
  • Serum Albumin / genetics*
  • Transcription Factors / metabolism*
  • Tumor Cells, Cultured

Substances

  • DNA-Binding Proteins
  • Serum Albumin
  • Transcription Factors