Studies into the mechanism of transcriptional activation by simian virus 40 large T antigen: Interactions with multiple components of the transcription complex

Simian virus 40 large T antigen is a promiscuous transcriptional activator of many viral and cellular promoters. The SV40 late promoter, a primary target for T antigen transcriptional activation contains a previously described T antigen activated element (TAU; SV40 nucs. 154 to 294). Within this element are overlapping octamer (OCT) and TEF-1 (SPH motif) binding sites (OCT/EF element). Using an OCT/TEF site as an upstream element in a simple promoter, we show that the TEF sites are necessary for transcriptional activation by T antigen, while octamer factor binding suppresses both basal activity and T antigen activation. This suggests that one function of T antigen in transcriptional activation of the late promoter is to alter factor binding at the OCT/TEF region to favor binding of factors to the TEF sites. TEF-1 also recognizes another site within the SV40 late promoter called GTIIc (SV40 nucleotides 262-270). T antigen can efficiently activate promoters containing this site as an upstream element also, suggesting that TEF-1 may be an important target of T antigen activation. To determine whether T antigen activates by directly interacting with the factors bound to one or both of these elements, full length T antigen, or segments of it, were fused to glutathione-S-transferase (GST fusions) or to the Gal4 1-147 DNA binding domain (Gal4 fusions). TEF-1 and the TATA binding protein (TBP) bound different regions of T antigen. the TATA binding protein (TBP) efficiently bound a GST fusion containing amino acids 5-172 (Region T1), whereas TEF-1 required a larger region, amino acids 5-383 (Region T5) to bind. The Gal4 fusions demonstrated that no region of T antigen could activate a promoter containing Gal4 binding sites. However, the Gal4 fusion with region T1, which binds only TBP, modestly activated the SV40 late promoter and the simple TEF-1/TATA promoter. Region T5, which binds both TBP and TEF-1, activated each promoter to levels equivalent to that of WT T antigen. The correlation of binding and activation suggests that T antigen causes activation through direct interactions with multiple factors in the transcription complexes

Broad adsorption of sepsis-related PAMP and DAMP molecules, mycotoxins, and cytokines from whole blood using CytoSorb^® sorbent porous polymer beads

<div><p>Objective</p><p>Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. In sepsis and septic shock, pathogen-associated molecular pattern molecules (PAMPS), such as bacterial exotoxins, cause direct cellular damage and/or trigger an immune response in the host often leading to excessive cytokine production, a maladaptive systemic inflammatory response syndrome response (SIRS), and tissue damage that releases DAMPs, such as activated complement and HMGB-1, into the bloodstream causing further organ injury. Cytokine reduction using extracorporeal blood filtration has been correlated with improvement in survival and clinical outcomes in experimental studies and clinical reports, but the ability of this technology to reduce a broader range of inflammatory mediators has not been well-described. This study quantifies the size-selective adsorption of a wide range of sepsis-related inflammatory bacterial and fungal PAMPs, DAMPs and cytokines, in a single compartment, <i>in vitro</i> whole blood recirculation system.</p><p>Measurements and main results</p><p>Purified proteins were added to whole blood at clinically relevant concentrations and recirculated through a device filled with CytoSorb^® hemoadsorbent polymer beads (CytoSorbents Corporation, USA) or control (no bead) device <i>in vitro</i>. Except for the TNF-α trimer, hemoadsorption through porous polymer bead devices reduced the levels of a broad spectrum of cytokines, DAMPS, PAMPS and mycotoxins by more than 50 percent.</p><p>Conclusions</p><p>This study demonstrates that CytoSorb^® hemoadsorbent polymer beads efficiently remove a broad spectrum of toxic PAMPS and DAMPS from blood providing an additional means of reducing the uncontrolled inflammatory cascade that contributes to a maladaptive SIRS response, organ dysfunction and death in patients with a broad range of life-threatening inflammatory conditions such as sepsis, toxic shock syndrome, necrotizing fasciitis, and other severe inflammatory conditions.</p></div

Adsorption of bacterial PAMPs with CS hemoadsorptive polymer beads or a control (no polymer) device from whole blood spiked with <i>S</i>. pyogenic exotoxin B, <i>Staph</i> TSST-1 or serum with <i>Staph aureus</i> alpha-toxin.

<p>Percent remaining from the mean ± SEM of 4 runs. * p<0.05.</p

Le Trône enchanté, conte indien traduit du persan. Tome 2 / . Par M. le baron Lescallier,...

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