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Transcription of a eukaryotic structural gene by RNA polymerase II requires the ordered assembly of general transcription factors on the promoter to form a pre-initiation complex. Here we analyze affinity-purified complexes at various stages of assembly to determine the mechanism of action of an acidic transcriptional activator. We show that the activator(More)
In prokaryotes and eukaryotes many gene activators work synergistically. For example, two dimers of lambda repressor interact to promote binding of these proteins to DNA, a reaction that is crucial at the repressor concentrations found in lysogens. In this case one of the bound dimers activates transcription, evidently by touching RNA polymerase. In another(More)
We show that derivatives of the yeast transcriptional activator GAL4, synthesized in and purified from E. coli, stimulate transcription of a mammalian gene (the adenovirus E4 gene) in a HeLa cell nuclear extract. Stimulation depended upon GAL4 binding sites inserted in the template. When the GAL4 sites were placed immediately upstream of the E4 TATA box,(More)
A striking characteristic of many different eukaryotic transcriptional activators is their ability to activate gene expression synergistically. Thus, for example, the rat glucocorticoid receptor and the yeast activator GAL4 cooperatively activate transcription of a mammalian gene bearing binding sites for each of the proteins: activation by both activators(More)
A central issue in eukaryotic transcriptional regulation is the mechanism by which promoter-specific transcription factors (activators) stimulate transcription. Two lines of evidence indicate that the general transcription factor TFIIB is a pivotal component in the mechanism by which an acidic activator functions. First, during assembly of the preinitiation(More)
The mammalian activator protein ATF stimulates transcription from the adenovirus E4 promoter by binding to multiple upstream promoter and enhancer elements. DNAase footprint analyses have revealed that there are cooperative interactions between ATF and TFIID (the mammalian TATA factor) when both are bound simultaneously to the promoter and that these(More)
The Fe(3)O(4) nanoparticles, tailored with maleimidyl 3-succinimidopropionate ligands, were conjugated with paclitaxel molecules that were attached with a poly(ethylene glycol) (PEG) spacer through a phosphodiester moiety at the (C-2')-OH position. The average number of paclitaxel molecules/nanoparticles was determined as 83. These nanoparticles liberated(More)
p53-mediated apoptosis is antagonized by growth factor stimulation. Here, we show that p53-dependent cell death induced by DNA damage was effectively prevented by mitogen activation. The levels of Bcl-2, Bcl-xL, and Bax were not altered by cisplatin treatment and mitogen rescue. Instead, the protection against p53-regulated apoptosis was mediated by at(More)
Organisms as diverse as bacteria and man contain genes that show transcriptional induction when the intracellular concentration of cAMP is increased. This regulated transcriptional response is mediated through specific promoter elements located, in general, upstream from the transcription start site. In Escherichia coli the element responsible for(More)
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