Title
Role of c-Jun and proximal phorbol 12-myristate-13-acetate-(PMA)-responsive elements in the regulation of basal and PMA-stimulated plasminogen-activator inhibitor-1 gene expression in HepG2
Author
Arts, J.
Grimbergen, J.
Bosma, P.J.
Rahmsdorf, H.J.
Kooistra, T.
Gaubius Laboratory, TNO-PG, Leiden, Netherlands Institut für Genetik, Forschungszentrum Karlsruhe, Germany TNO Preventie en Gezondheid
Publication year
1996
Abstract
Experiments were designed to clarify the role of c-Jun/c-Fos and of putative phorbol 12-myristate-13-acetate-(PMA)-responsive elements (TREs) in the induction of plasminogen-activator inhibitor 1 (PAI-1) gene transcription in the human hepatoma cell line HepG2 by activators of protein kinase C (PKC). Treatment of HepG2 cells with the phorbol ester PMA or serum rapidly and transiently increased c-Jun and c-Fos mRNA and protein levels prior to PAI-1 induction. This induction of PAI-1 gene transcription was found to be dependent on ongoing protein synthesis. An essential role of c-Jun and c-Fos in basal and PMA-stimulated transcription of the PAI-1 gene is demonstrated by our finding that antisense c-jun and c-fos oligodeoxynucleotides both strongly reduced basal and PMA-stimulated PAI-1 synthesis. Since it has already been shown that two TREs between positions -58 and -50 and between -79 and -72 of the PAI-1 promoter are essential for basal and PMA-induced PAI-1 promoter activity, we examined binding of nuclear proteins to these elements. The protein-binding activity to the TRE between positions -79 and -72 shows very strong PMA induction of an unknown factor, which is not related to cJun or c-Fos. The TRE binding between positions -58 and -50 forms two complexes, both containing c-Jun protein. The faster migrating complex primarily contains c-Jun homodimers. The amount of the faster migrating complex is enhanced more than 30-fold in PMA-treated cells, due to a strongly increased binding of c-Jun homodimers and, to a minor extent, to binding of c-Jun/c-Fos heterodimers. Dissociation experiments suggest that the c-Jun/c-Fos heterodimers bind with much lower affinity compared to binding of c-Jun homodimers. Together with the finding that both antisense c-jun and antisense c-fos oligodeoxynucleotides reduced the amount of c-Jun homodimer, we conclude that binding of c-Jun homodimer to the TRE at positions -58 to -50 is important in the basal activity and PMA activation of the PAI-1 promoter in HepG2 cells. Chemicals/CAS: Culture Media; Cycloheximide, 66-81-9; Oligonucleotides, Antisense; Plasminogen Activator Inhibitor 1; Protein Synthesis Inhibitors; Proto-Oncogene Proteins c-fos; Proto-Oncogene Proteins c-jun; RNA, Messenger; Tetradecanoylphorbol Acetate, 16561-29-8; Transcription Factor AP-1
Subject
Biology
Activator protein-1
Gene expression
Hepatocytes
Phorbol-12 myristate-13-acetate-responsive element
Plasminogen-activator inhibitor 1
antisense oligodeoxynucleotide
messenger rna
phorbol 13 acetate 12 myristate
plasminogen activator inhibitor 1
article
cell strain hepg2
controlled study
gene expression regulation
gene induction
human
human cell
oncogene c fos
oncogene c jun
priority journal
Base Sequence
Binding Sites
Cell Line
Culture Media
Cycloheximide
Gene Expression Regulation
Genes, fos
Genes, jun
Humans
Kinetics
Oligonucleotides, Antisense
Plasminogen Activator Inhibitor 1
Protein Synthesis Inhibitors
Proto-Oncogene Proteins c-fos
Proto-Oncogene Proteins c-jun
RNA, Messenger
Tetradecanoylphorbol Acetate
Transcription Factor AP-1
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DOI
https://doi.org/10.1111/j.1432-1033.1996.00393.x
TNO identifier
233546
ISSN
0014-2956
Source
European Journal of Biochemistry, 241 (2), 393-402
Document type
article