Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Many eukaryotic RNA polymerase II promoters contain initiator elements which direct accurate transcription in a TATA-independent manner. The PEA3/Ets-binding site (PEA3/EBS) is a common enhancer element in eukaryotic genes and is also found near the transcriptional start sites of many TATA-less promoters. We demonstrate that two PEA3/EBSs driving expression of the luciferase reporter gene, function as a minimal transcriptional initiator element. Maximal levels of transcription was achieved when two PEA3/EBSs, in either orientation, were located on the same face of the DNA helix, and the sites could be separated by up to three helical turns. In vitro transcription start sites directed by PEA3/EBS elements were clustered on either side of the upstream PEA3/EBS and were abolished by immunodepletion of GA-binding protein (GABP) from FM3A cell nuclear extracts. In vivo, co-transfection of GABPalpha and GABPbeta expression vectors enhanced reporter gene expression driven from PEA3/EBS initiator elements. Like other initiator elements, the PEA3/EBS elements were activated synergistically by upstream Sp1-binding sites. Thus, our results establish GABP as both a transcriptional activator factor and as an initiator factor.
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PMID:GA-binding protein-dependent transcription initiator elements. Effect of helical spacing between polyomavirus enhancer a factor 3(PEA3)/Ets-binding sites on initiator activity. 936 Sep 80

We have studied the assembly of GA-binding protein (GABP) in solution and established the role of DNA in the assembly of the transcriptionally active GABPalpha(2)beta(2) heterotetrameric complex. GABP binds DNA containing a single PEA3/Ets-binding site (PEA3/EBS) exclusively as the alphabeta heterodimer complex, but readily binds as the GABPalpha(2)beta(2) heterotetramer complex on DNA containing two PEA3/EBSs. Positioning of the PEA3/EBSs on the same face of the DNA helix stabilizes heterotetramer complex binding. These observations suggest that GABPalphabeta heterodimers are the predominant molecular species in solution and that DNA containing two PEA3/EBSs promotes formation of the GABPalpha(2)beta(2) heterotetrameric complex. We analyzed the assembly of GABPalpha(2)beta(2) heteromeric complexes in solution by analytical ultracentrifugation. GABPalpha exists as a monomer in solution while GABPbeta exists in a monomer-dimer equilibrium (K(d) = 1.8 +/- 0.27 microM). In equimolar mixtures of the two subunits, GABPalpha and GABPbeta formed a stable heterodimer, with no heterotetramer complex detected. Thus, GABP exists in solution as the heterodimer previously shown to be a weak transcriptional activator. Assembly of the transcriptionally active GABPalpha(2)beta(2) heterotetramer complex requires the presence of specific DNA containing at least two PEA3/EBSs.
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PMID:The alpha and beta subunits of the GA-binding protein form a stable heterodimer in solution. Revised model of heterotetrameric complex assembly. 1071 87