Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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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PMID:Multiple transforming growth factor-beta-inducible elements regulate expression of the plasminogen activator inhibitor type-1 gene in Hep G2 cells. 198 37

Type 1 plasminogen activator inhibitor (PAI-1) is the major physiological inhibitor of plasminogen activation, inhibiting both tissue- and urokinase-type plasminogen activators. In HTC rat hepatoma cells, glucocorticoids increase PAI-1 activity, antigen and mRNA accumulation 3- to 5-fold; this increase is due solely to an increase in the rate of PAI-1 gene transcription. We have identified the cis-acting sequences in the 5'-flanking sequence of the HTC PAI-1 gene that mediate this induction. Analysis of a series of hybrid genes containing various portions of the PAI-1 5'-flanking region fused to the chloramphenicol acetyltransferase reporter gene transfected into HTC cells localized the region involved in the transcriptional regulation by glucocorticoids to between -1237 and -764. Electrophoretic mobility shift assays and DNase-I protection assays showed that a glucocorticoid response element (GRE) 15-mer located at -1212 bound the glucocorticoid receptor DNA-binding domain protein in a concentration-dependent manner. Mutations created within this GRE eliminated its ability both to confer a glucocorticoid response and to bind the glucocorticoid receptor. When placed upstream of a heterologous promoter in either orientation, this GRE conferred glucocorticoid inducibility. We, therefore, conclude that the sole cis-acting sequence required for the glucocorticoid response of the PAI-1 gene in rat HTC hepatoma cells is the GRE at -1212.
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PMID:Mechanism of glucocorticoid induction of the rat plasminogen activator inhibitor-1 gene in HTC rat hepatoma cells: identification of cis-acting regulatory elements. 824 19

In order to investigate the molecular basis for the regulated expression of plasminogen activator inhibitor type 2 (PAI-2), we sought to identify monocyte-derived nuclear factors which interact with the PAI-2 gene. We have explored the application of Southwestern blot mapping as an approach for identifying specific DNA-protein interactions and targeting potential regulatory DNA elements. The procedure involves an initial global screening of a crude preparation of nuclear proteins with radiolabelled DNA fragments (200-300 bp) derived from a large region (8.8 kb) of PAI-2. The bound DNA fragments are eluted and their location within PAI-2 mapped by Southern blot hybridization analysis. We have used this procedure to examine the differential binding of nuclear factors from the U937 monocytic cell in the absence and in the presence of the differentiating agent, 12-phorbol 13-myristate acetate (PMA), in order to identify proteins that bind specifically to the 5' flanking promoter region and first intron of PAI-2. Eleven DNA-binding proteins ranging in molecular mass from 27 to 92 kDa were identified, and the results define three regions of the gene which contain DNA-binding sites which may be involved in the transcriptional regulation of PAI-2. Deletion analysis using a series of 5' deletion mutants spanning PAI-2 fused to a chloramphenicol acetyltransferase-encoding reporter gene (cat) demonstrates that two of the regions identified by Southwestern blot mapping contain elements which can function to modulate PAI-2 expression in transient transfections of U937 cells.
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PMID:Southwestern blot mapping of potential regulatory proteins binding to the DNA encoding plasminogen activator inhibitor type 2. 826 78