In vitro interaction between the N-terminus of the Ewing’s sarcoma protein and the subunit of RNA polymerase II hsRPB7

In vivo and in vitro expressed N-terminal sequence of EWS (EAD) and hsRPB7 (subunit of human RNA polymerase II) were probed for protein–protein interactions using pull-down assays. In result, it was found that the proteins 57Z (residues 1–57 of EAD) and hsRPB7 interact in vitro forming a stable complex. The direct interaction between 57z and hsRPB7 indicate that DHR-related peptides and other small molecules, targeted to N-terminus of EWS might possess therapeutic potentialities as anti-cancer agents to function as inhibitors of EAD-mediated transactivation.     

Study of the inhibitory effect of fatty acids on the interaction between DNA and polymerase β

The binding of human DNA polymerase β (pol β) to DNA template-primer duplex and single-stranded DNA in the absence or presence of pol β inhibitors has been studied using a surface plasmon resonance biosensor. Two fatty acids, linoleic acid and nervonic acid, were used as potent pol β inhibitors. In the interaction between pol β and DNA, pol β could bind to ssDNA in a single binding mode, but bound to DNA template-primer duplexes in a parallel mode. Both pol β inhibitors prevented the binding of pol β to the single strand overhang and changed the binding from parallel to single mode. The affinities of pol β to the template-primer duplex region in the presence of nervonic acid or linoleic acid were decreased by 20 and 5 times, respectively. The significant inhibitory effect of nervonic acid on the pol β-duplex interaction was due to both a 2-fold decrease in the association rate and a 9-fold increase in the dissociation rate. In the presence of linoleic acid, no significant change of association rate was observed, and the decrease in binding affinity of pol β to DNA was mainly due to 7-fold increase in the dissociation rate. Published in Russian in Biokhimiya, 2009, Vol. 74, No. 7, pp. 1000–1006. These authors contributed equally.     

Lack of association between TNF-α gene promoter polymorphisms and pancreatitis: a meta-analysis

Background/Aims

Tumor necrosis factor alpha (TNF-α) is a major proinflammatory cytokine involved in the etiology of pancreatitis. The association between pancreatitis and the − 308G>A and − 238G>A polymorphisms in TNF-α gene has been analyzed in several studies, but results have been inconsistent. The purpose of this study was to integrate previous findings and explore whether these polymorphisms are associated with susceptibility and severity to pancreatitis.

Methods

A meta-analysis was performed by searching PubMed, Cochrane Library, and ScienceDirect databases. Data were extracted using predefined form and odds ratios (OR) with 95% confidence intervals (CI) were calculated.

Results

Our meta-analysis of a total of 1569 pancreatitis cases and 1330 control subjects from twelve published case–control studies for the − 308G>A polymorphism (OR 0.98; 95% CI 0.83–1.17), and of 480 cases and 302 controls from four studies for the − 238G>A polymorphism (OR 0.92; 95% CI 0.58–1.47) did not show any significant associations of susceptibility to pancreatitis with the variant GA+AA genotypes compared with the GG genotype. An association between severity of acute pancreatitis and − 308G>A polymorphism was not found either (OR 0.93; 95% CI 0.69–1.24).

Conclusion

Polymorphisms in two sites of TNF-α gene promoter do not alter the risk of pancreatitis.