Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.99.3 (PRE)
 1,923 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The antirheumatic gold salt aurothiomalate (AuTM) has cellular actions that are consistent with modulation of gene expression. We have tested the hypothesis that an important mode of action of AuTM is inhibition of binding of certain transcription factors to regulatory elements in DNA. The chemistry of transcription factors containing the zinc finger motif makes them candidates for such an interaction with AuTM. In this regard, the interaction of a steroid hormone receptor, the progesterone receptor (PR), with its DNA response element (PRE) was chosen as a suitable model. Nuclear extracts of T-47D human breast cancer cells rich in PR were incubated with radiolabeled PRE, and binding was determined by gel retardation assay. Preincubation of nuclear extract with AuTM caused a concentration-dependent inhibition of binding of PR to PRE (IC50, approximately 3 microM). Other metal ions inhibited binding at higher concentrations, in a rank order correlating with their binding affinity for thiols. Thiomalic acid had no effect in the absence of gold in this system. To test the effect of AuTM on PR-mediated transcription, we transfected the progestin-inducible expression vector pMSG-CAT into T-47D cells. Transfected cells were incubated in the absence or presence of AuTM and treated with the synthetic progestin ORG2058, to induce chloramphenicol acetyl transferase (CAT) activity. With 10 and 100 microM AuTM, there was inhibition to 67 +/- 3% (p = 0.012) and 42 +/- 8% (p = 0.008) of CAT specific activity, respectively, compared with controls. These results demonstrate that AuTM can regulate gene expression and that inhibition of binding of a transcription factor to its response element is a likely mechanism. This provides a molecular model for further study of the antirheumatic action of gold salts.
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PMID:Inhibition of DNA binding and transcriptional activity of a nuclear receptor transcription factor by aurothiomalate and other metal ions. 194 34

UvrA is the initial DNA damage-sensing protein in bacterial nucleotide excision repair. Each protomer of the UvrA dimer contains two ATPase domains, that belong to the family of ATP-binding cassette domains. Three structural domains are inserted in these ATPase domains: the insertion domain (ID) and UvrB binding domain (in ATP domain I) and the zinc-finger motif (in ATP domain II). In this paper we analyze the function of the ID and the zinc finger motif in damage specific binding of Escherichia coli UvrA. We show that the ID is not essential for damage discrimination, but it does stabilize UvrA on the DNA, most likely by forming a clamp around the DNA helix. We present evidence that two conserved arginine residues in the ID contact the phosphate backbone of the DNA, leading to strand separation after the ATPase-driven movement of the ID's. Remarkably, deletion of the ID generated a phenotype in which UV-survival strongly depends on the presence of photolyase, indicating that UvrA and photolyase form a ternary complex on a CPD-lesion. The zinc-finger motif is shown to be important for the transfer of the damage recognition signal to the ATPase of UvrA. In the absence of this domain the coupling between DNA binding and ATP hydrolysis is completely lost. Mutation of the phenylalanine residue in the tip of the zinc-finger domain resulted in a protein in which the ATPase was already triggered when binding to an undamaged site. As the zinc-finger motif is connected to the DNA binding regions on the surface of UvrA, this strongly suggests that damage-specific binding to these regions results in a rearrangement of the zinc-finger motif, which in its turn activates the ATPase. We present a model how damage recognition is transmitted to activate ATP hydrolysis in ATP binding domain I of the protein.
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PMID:Role of the insertion domain and the zinc-finger motif of Escherichia coli UvrA in damage recognition and ATP hydrolysis. 2139 72