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Adenovirus-mediated transfer of CCAAT/enhancer-binding protein-alpha identifies a dominant antiproliferative role for this isoform in hepatocytes.

Publication ,  Journal Article
Diehl, AM; Johns, DC; Yang, S; Lin, H; Yin, M; Matelis, LA; Lawrence, JH
Published in: J Biol Chem
March 29, 1996

CCAAT/enhancer-binding protein (C/EBP) isoforms are thought to be important regulators of the hepatocyte phenotype. However, the specific physiological roles of different isoforms are poorly understood because hepatocytes express multiple C/EBPs, and various isoforms have overlapping functions. To identify the functions of C/EBPalpha in mature hepatocytes, replication-defective adenovirus vectors were used to efficiently and homogeneously overexpress the mouse C/EBPalpha gene in a SV40 virus-conditionally transformed rat hepatocyte line that can be induced to express C/EBPbeta and C/EBPdelta but that has little endogenous C/EBPalpha expression. Hepatocytes were infected with a recombinant adenovirus vector carrying the cDNA for C/EBPalpha driven by Rous sarcoma virus promoter elements (AdCEBPalpha) or a similar vector carrying the Escherichia coli lacZ gene (Adbetagal). Staining for beta-galactosidase demonstrated an infection efficiency of 100% at a multiplicity of infection of 25 plaque-forming units/cell and persistence of foreign gene expression for at least 9 days. Cultures infected with AdCEBPalpha had 50-fold higher levels of C/EBPalpha mRNA and protein than those infected with Ad-beta-gal, but similar expression of C/EBP-beta. Infection with AdCEBPalpha inhibited proliferation in cells expressing little C/EBPbeta, even when proliferation was driven by the SV40 transforming antigen, and also blunted mitogenic induction of the c-myc proto-oncogene in nontransformed cells with high levels of C/EBPbeta. Although overexpression of C/EBPalpha consistently increased C/EBPalpha DNA binding activity, it was not sufficient for albumin expression. Infection with AdCEBPalpha only increased albumin mRNA levels in nontransformed cells that also expressed relatively high levels of C/EBPbeta. Thus, in hepatocytes, C/EBPalpha has a dominant antiproliferative function, but must interact with other factors to regulate hepatocyte-specific gene expression.

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Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

March 29, 1996

Volume

271

Issue

13

Start / End Page

7343 / 7350

Location

United States

Related Subject Headings

  • Transfection
  • Temperature
  • Simian virus 40
  • Recombinant Proteins
  • Rats
  • RNA, Messenger
  • Proto-Oncogene Proteins c-myc
  • Proto-Oncogene Mas
  • Promoter Regions, Genetic
  • Nuclear Proteins
 

Citation

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Diehl, A. M., Johns, D. C., Yang, S., Lin, H., Yin, M., Matelis, L. A., & Lawrence, J. H. (1996). Adenovirus-mediated transfer of CCAAT/enhancer-binding protein-alpha identifies a dominant antiproliferative role for this isoform in hepatocytes. J Biol Chem, 271(13), 7343–7350. https://doi.org/10.1074/jbc.271.13.7343
Diehl, A. M., D. C. Johns, S. Yang, H. Lin, M. Yin, L. A. Matelis, and J. H. Lawrence. “Adenovirus-mediated transfer of CCAAT/enhancer-binding protein-alpha identifies a dominant antiproliferative role for this isoform in hepatocytes.J Biol Chem 271, no. 13 (March 29, 1996): 7343–50. https://doi.org/10.1074/jbc.271.13.7343.
Diehl AM, Johns DC, Yang S, Lin H, Yin M, Matelis LA, et al. Adenovirus-mediated transfer of CCAAT/enhancer-binding protein-alpha identifies a dominant antiproliferative role for this isoform in hepatocytes. J Biol Chem. 1996 Mar 29;271(13):7343–50.
Diehl, A. M., et al. “Adenovirus-mediated transfer of CCAAT/enhancer-binding protein-alpha identifies a dominant antiproliferative role for this isoform in hepatocytes.J Biol Chem, vol. 271, no. 13, Mar. 1996, pp. 7343–50. Pubmed, doi:10.1074/jbc.271.13.7343.
Diehl AM, Johns DC, Yang S, Lin H, Yin M, Matelis LA, Lawrence JH. Adenovirus-mediated transfer of CCAAT/enhancer-binding protein-alpha identifies a dominant antiproliferative role for this isoform in hepatocytes. J Biol Chem. 1996 Mar 29;271(13):7343–7350.

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

March 29, 1996

Volume

271

Issue

13

Start / End Page

7343 / 7350

Location

United States

Related Subject Headings

  • Transfection
  • Temperature
  • Simian virus 40
  • Recombinant Proteins
  • Rats
  • RNA, Messenger
  • Proto-Oncogene Proteins c-myc
  • Proto-Oncogene Mas
  • Promoter Regions, Genetic
  • Nuclear Proteins