Multiple transforming growth factor-beta-inducible elements regulate expression of the plasminogen activator inhibitor type-1 gene in Hep G2 cells.

D R Westerhausen; W E Hopkins; J J Billadello

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PubMed · 1985937

Multiple transforming growth factor-beta-inducible elements regulate expression of the plasminogen activator inhibitor type-1 gene in Hep G2 cells.

D R Westerhausen·W E Hopkins·J J Billadello

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Abstract

Regulation of plasminogen activation by plasminogen activator inhibitor type-1 (PAI-1) is a critical feature of many biological processes. Transforming growth factor-beta (TGF-beta) induces PAI-1 mRNA and protein in several types of cultured cells, including Hep G2 cells. The present study was performed to define mechanisms by which PAI-1 gene expression is regulated by TGF-beta. Nuclear run-on assays performed on Hep G2 cells stimulated with TGF-beta for 6 h showed a 3.8-fold increase in PAI-1 gene transcription. TGF-beta increased the half-life of PAI-1 mRNA in Hep G2 cells 2.5-fold over control values. To characterize transcriptional regulatory mechanisms, we constructed chimeric genes containing PAI-1 5'-flanking DNA fused upstream of the bacterial chloramphenicol acetyltransferase gene in the vector pSVOCAT and transfected Hep G2 cells. Promoter deletion analysis demonstrated that sequences between -791 and -328 and -328 to -186 base pairs upstream of the PAI-1 gene cap site contain TGF-beta responsive elements that conferred TGF-beta inducibility in an orientation and position-independent manner. Further characterization of the larger TGF-beta-inducible enhancer (-791 to -328) located a TGF-beta-inducible element at nucleotides -791 to -546 upstream of the PAI-1 gene cap site. These results demonstrate that PAI-1 gene regulation by TGF-beta in Hep G2 cells is mediated both at a transcriptional level by two specific inducible elements, as well as by post-transcriptional mechanisms.

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Blotting, Northern Chimera Chloramphenicol O-Acetyltransferase Gene Expression Regulation Humans Plasminogen Inactivators Promoter Regions, Genetic Protein Synthesis Inhibitors RNA, Messenger Transcription, Genetic Transforming Growth Factors Tumor Cells, Cultured Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S.

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D R Westerhausen, W E Hopkins, J J Billadello. 1991-01-15. Multiple transforming growth factor-beta-inducible elements regulate expression of the plasminogen activator inhibitor type-1 gene in Hep G2 cells.. https://pubmed.ncbi.nlm.nih.gov/1985937/

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