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

We have characterized a transcriptional enhancer of the human urokinase-type plasminogen activator (uPA) gene and found a regulatory element required for co-operation between a PEA3--AP-1 element and an AP-1 site in the enhancer. We designated this regulatory element co-operation mediator (COM). Both the PEA3--AP-1 element, the AP-1 site and the COM are required for efficient phorbol ester induction of transcription from the uPA promoter in the HepG2 hepatoma cell line. We show that the COM is also required for co-operation between the PEA3--AP-1 element and a glucocorticoid response element, both in the presence or absence of TPA, indicating that the COM is generally capable of mediating synergism between inducible enhancer elements. The COM contains multiple overlapping binding sites for nuclear proteins, designated uPA enhancer factors 1-4 (UEF-1-4). We have identified putative binding sites for UEF-1, -2 and -3. The UEF-1 and -3 sites in the uPA enhancer are highly conserved between species. We demonstrate the binding of UEF-3 to the NIP element, a previously characterized regulatory element in the human interleukin-3 and stromelysin promoters, suggesting that this factor plays a role in regulation of a variety of genes.
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PMID:A regulatory element that mediates co-operation between a PEA3-AP-1 element and an AP-1 site is required for phorbol ester induction of urokinase enhancer activity in HepG2 hepatoma cells. 133 May 39

Basal as well as induced transcription from the human urokinase-type plasminogen activator gene requires an enhancer containing two elements, a combined PEA3/AP-1 and a consensus AP-1 site. The integrity of each of these binding sites as well as their cooperation is required for activating transcription. The two elements are separated by a 74-base pair cooperation mediating (COM) region required for the cooperation between the transactivating sites. The COM region contains binding sites for four different unidentified urokinase-type plasminogen activator enhancer factors (UEF 1 to 4), all four required for correct COM activity. We have purified UEF3 from HeLa nuclear extracts by several chromatographic steps including DNA affinity purification. Purification and UV cross-linking data showed that UEF3 is a complex of three polypeptides (p40, p50, and p64). Amino acid sequence from one peptide of p64 was obtained, which showed no homology to other known proteins. Both crude and purified UEF3 specifically bound to the sequence TGACAG as shown by electrophoretic mobility shifts and methylation interference studies. DNA-binding specificity of purified UEF3 was identical to that of NIP, a non-characterized factor binding and regulating multiple AP-1-regulated promoters like stromelysin and interleukin-3. Thus UEF3 appears to be a general DNA-binding factor involved in modulating the transcriptional response of AP-1 containing promoters.
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PMID:Purification and characterization of UEF3, a novel factor involved in the regulation of the urokinase and other AP-1 controlled promoters. 863

The inducible uPA enhancer contains two phorbol ester responsive elements: the combined PEA3/AP-1A and a downstream AP-1B site. The integrity of all three sites is essential for enhancer activity. The interposed 74 bp long DNA region (COM, Cooperation Mediator) is in turn required for the synergistic action of the PEA3/AP-1 and AP-1 sites. Here we present a characterization of the COM sequence: our results show that COM and COM-binding proteins (UEF, Urokinase Enhancer Factors) may play a structural role in the induction of the uPA enhancer by phorbol-myristate-acetate (TPA). (1) COM has a bipartite structure (uCOM and dCOM) and each half contributes by about 50% to the COM-mediated TPA induction. (2) COM function is strictly dependent on its position, but not on its orientation and neither the entire COM nor individual UEF-binding sites can directly transactivate a test promoter. (3) The requirement for COM in TPA-induction is partly eliminated by the deletion of COM sequence. However, also in the COM-deleted enhancer, integrity of the PEA3/AP-1A and AP-1B sites is essential for enhancer function. We conclude that COM and COM-binding proteins provide a structural surface which facilitates the cooperation between the transactivator proteins bound at the PEA3/AP-1A and AP-1B sites. Sequences homologous to uCOM are found in the promoters of other inducible genes, coding for proteases, cytokines and chemokines: for example, in the promoter of the MIP-1alpha/LD78 chemokine gene, a 15/18 nucleotides identity is found in a region mediating positive and negative functions in TPA induction. Thus, COM-like elements represent a general enhancer function which, although lacking an intrinsic transactivating capacity, modulates the synergism between transcription factors bound to distant sites.
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PMID:Functional characterization of COM, a DNA region required for cooperation between AP-1 sites in urokinase gene transcription. 900 Jan 29

The enhancer of the inducible urokinase gene depends on three essential but not sufficient transactivating elements, an upstream PEA3/AP-1A and a downstream AP-1B site. Enhancer activity also requires the interposed 74-base pair-long cooperation mediator (COM) region that allows transcriptional synergism between the transactivating sites. The 5'-half of COM (uCOM) forms four retarded complexes with HeLa or Hep-G2 nuclear proteins (UEF-1-4). We have identified the binding sequence for UEF-4 and generated uCOM elements uniquely mutated in the UEF-4-binding site or uniquely binding UEF-4. Introduction of these and other mutations in the context of the urokinase enhancer showed that all uCOM sites are important for enhancer activity but that UEF-4 and UEF-1 plus UEF-2/3 can substitute for each other, suggesting functional redundancy of urokinase enhancer factors. UEF-4 was purified from HeLa nuclear extract by affinity chromatography and shown to contain two polypeptides of 105 and 65 kDa, respectively, of which at least the former was endowed with DNA binding activity.
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PMID:Characterization of UEF-4, a DNA-binding protein required for transcriptional synergism between two AP-1 sites in the human urokinase enhancer. 929 42

The inducible urokinase enhancer contains three essential elements: a combined PEA3/AP1 and a downstream AP1 site, separated by a 74-bp DNA region called COM (cooperation mediator), that is required for the synergism between the three sites. The 5' half of COM (uCOM) forms four retarded complexes with HeLa or HepG2 nuclear proteins (UEF1-4). We now demonstrate that the UEF4 complex is the transcription factor Oct-1. Because of functional redundancy of the UEF sites, single mutations in UEF4 have no phenotype; we have changed UEF4 from a low to a high affinity binding site for Oct-1. In vitro, this mutation increases the DNA binding of Oct-1 and disturbs the binding of the Prep-Pbx complexes to the nearby UEF3 site. In vivo, this mutation reduces the basal transcriptional activity of the urokinase enhancer, while not affecting its phorbol ester inducibility. This is in keeping with the effect of the deletions of the COM region, which result in an increase in the basal level and, as a consequence, in the loss of 4beta-phorbol 12-myristate 13-acetate inducibility. Oct-1 therefore is not involved in the inducibility of the urokinase enhancer but only in determining its basal activity level.
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PMID:Oct-1 specifically binds the UEF4 site of the human AP1-regulated urokinase enhancer. 1095 Dec 1