Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Primary fetal human adrenocortical cells of definitive zone origin were transfected by electroporation with pSV3neo, a plasmid coding for SV40 T antigen and neo, which confers resistance to the antibiotic G418. The clones obtained proliferated for 30 to 40 population doublings after isolation when grown under standard medium conditions, and then entered 'crisis'. When early-passage clones were incubated with cyclic AMP (1:1 N6-monobutyryl and 8-bromo analogues), cell rounding was observed, as in primary cultures of human adrenocortical cells. As previously shown in bovine adrenocortical cells, rounding was inhibited with a monoclonal antibody against urokinase plasminogen activator but not with a monoclonal antibody against tissue plasminogen activator. The regulation of the steroidogenic pathway in clones was investigated. The effects of cyclic AMP and activation of protein kinase C were examined in cells maintained in defined medium or in the presence of serum. 17 alpha-Hydroxylase was strongly induced by cyclic AMP, as evidenced by Northern blotting and by the conversion of progesterone or 25-hydroxy-[1,2-3H]cholesterol, this induction being blocked by low concentrations of 12-O-tetradecanoylphorbol-13-acetate (TPA). Cholesterol side-chain cleavage enzyme was strongly induced by cyclic AMP, and clones also showed low activities of 21-hydroxylase and 11 beta-hydroxylase. Under all circumstances levels of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), as assessed by Northern blotting or by conversion of 25-hydroxycholesterol, were very low. 3 beta-HSD was not induced by cyclic AMP or TPA alone, but was induced by the combination of the two agents. The regulation of 17 alpha-hydroxylase and 3 beta-HSD resembles that previously described in primary cultures of human fetal adrenocortical cells. Thus, transfection with SV40 T antigen resulted in the production of clones which preserve the unique characteristics of the human adrenal cortex.
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PMID:Expression of 17 alpha-hydroxylase and 3 beta-hydroxysteroid dehydrogenase in fetal human adrenocortical cells transfected with SV40 T antigen. 132 52

The RAW264 murine macrophage cell line was used as a model to examine the role of the tat and nef gene products in the transcription regulation of the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) in macrophages. Contrary to claims that the activity of the HIV-1 LTR responds poorly in rodent cells to trans activation by the viral tat gene product, cotransfection of RAW264 cells with a tat expression plasmid in transient transfection assays caused a > 20-fold increase in reporter gene expression that was inhibited by mutations in the TAR region. RAW264 cells stably transfected with the tat plasmid displayed similarly elevated HIV-1 LTR-driven reporter gene activity. By contrast to previous reports indicating a negative role for nef in HIV transcription, cotransfection of RAW264 cells with a nef expression plasmid trans activated the HIV-1 LTR driving either a chloramphenicol acetyltransferase or a luciferase reporter gene. The action of nef was specific to the LTR, as expression of nef had no effect on the activity of the simian virus 40, c-fms, urokinase plasminogen activator, or type 5 acid phosphatase promoter. trans-activating activity was also manifested by a frameshift mutant expressing only the first 35 amino acids of the protein. The effects of nef were multiplicative with those of tat gene product and occurred even in the presence of bacterial lipopolysaccharide, which itself activated LTR-directed transcription. Examination of the effects of selected mutations in the LTR revealed that neither the kappa B sites in the direct repeat enhancer nor the TAR region was required as a cis-acting element in nef action. The action of nef was not species restricted; it was able to trans activate in the human monocyte-like cell line Mono Mac 6. The presence of a nef expression cassette in a neomycin phosphotransferase gene expression plasmid greatly reduced the number of G418-resistant colonies generated in stable transfection of RAW264 cells, and many of the colonies that were formed exhibited very slow growth. The frameshift mutant was also active in reducing colony generation. Given the absence of any effect of the frameshift mutation on nef function, its actions on macrophage growth and HIV transcription are discussed in terms of the role of the N-terminal 30 amino acids and of stable secondary structures in the mRNA.
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PMID:Effects of the tat and nef gene products of human immunodeficiency virus type 1 (HIV-1) on transcription controlled by the HIV-1 long terminal repeat and on cell growth in macrophages. 823 Apr 18

Increased thromboresistance through the release of lytic agents by endothelial cells may improve the patency of endothelial lined prosthetic grafts. We have evaluated the expression of urokinase from cells transduced with a retrovirus containing the gene for a human preprourokinase. Endothelial cells were enzymatically harvested from canine external jugular vein in nine animals and grown to confluence in culture. One-third of these cells served as controls, and the remaining two-thirds were transduced via incubation with an LXSN-type retroviral vector carrying the urokinase gene and a neomycin resistance gene. Successfully transduced cells were selected by incubation with 400 micrograms/mL G418 and pure cultures grown to confluence. Supernatants from confluent control and experimental cell cultures after 48 hours in defined, serum-free medium were assayed for human urokinase concentration and overall enzyme activity. ELISA quantitation of concentration using mouse antihuman urokinase antibody showed 0.15 +/- 0.11 ng/mL/hr/10(6) cells in the transduced cell supernatant; no measurable concentration was found in the control cells. (P < 0.01) Overall (human plus canine) enzyme activity of urokinase was determined using an indirect spectrophotometric assay based on plasminogen activation (ploug U/mL). Transduced cells showed activities of 0.12 at 10 days and 0.45 at confluence; control cell activity was 0.0 and 0.15, respectively. (P < 0.05) These data show that endothelial cells can be transduced with a urokinase expressing gene that increases the release of this thrombolytic agent. Lining small diameter prosthetic grafts with these cells may improve their thromboresistance and long-term patency.
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PMID:Urokinase expression in transduced endothelial cells. 871 57

Pro-UKS1 was designed as a thrombin-resistant derivative of pro-urokinase (pro-UK) by introducing a glycosylation site using site-directed mutagenesis. An expression plasmid for pro-UKS1, pMo1UKS1SEd1-5, was constructed and introduced into Namalwa KJM-1 cells (Hosoi et al., 1988), and cells resistant to G418 and Methotrexate (MTX) were obtained. Amongst them, the highest pro-UKS1 producer (resistant to 500 nM of MTX), clone 41-8, was selected and further characterized. Clone 41-8 was cultured in serum-free ITPSGF medium (Hosoi et al., 1988). Under the conventional conditions, the concentration of pro-UKS1 reached 26 micrograms ml-1. Addition of glucose and tri-iodothyronine (T3) improved productivity, and the maximal productivity of pro-UKS1 was 67 micrograms ml-1 day-1. In this conditioned medium, content of pro-UKS1 was above 80% of total proteins.
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PMID:Stabile production of a thrombin resistant pro-urokinase derivative (PRO-UKS1) by Namalwa KJM-1 cells adapted to serum-free medium. 898 99

Pro-UK delta GS1 was designed as a long-life and thrombin-resistant derivative of pro-urokinase (pro-UK) by deleting the growth factor domain of pro-UK and introducing a glycosylation site near the thrombin cleaving site for thrombin-resistance using site-directed mutagenesis. An expression plasmid for pro-UKDGS1, pIH1UK delta GS1SEd1-5 was constructed and introduced into Namalwa KJM-1, a lymphoblastoid cell line adapted to serum-free medium, and cells resistant to G418 and Methotrexate (MTX) were obtained. Amongst them, the highest pro-UK delta GS1 producer (resistant to 200 nM of MTX), clone 2-9, was selected and used for further studies. Under the conventional conditions, i.e. at 37 degrees C in serum-free ITPSGF medium (based on RPMI-1640 medium), the oligosaccharide structure of pro-UK delta GS1 produced by clone 2-9 mainly consisted of fucose (Fuc)-containing biantennary complex-type oligosaccharide. Addition of dexamethasone (Dex), changed the carbohydrate contents in the media, and a shift down of incubation temperature caused a change in oligosaccharide structure of pro-UK delta GS1 from mainly Fuc-containing biantennary to mainly Fuc-containing tri- and tetraantennary complex-type oligosaccharide. The modulated pro-UK delta GS1 showed superior in vivo activity for a canine femoral thrombosis formed by inserting a copper-coil.
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PMID:Modulation of oligosaccharide structure of a pro-urokinase derivative (pro-UK delta GS1) by changing culture conditions of a lymphoblastoid cell line Namalwa KJM-1 adapted to serum-free medium. 898 1