摘要：

A role for the Epstein-Barr virus small RNA species EBER-1 in the regulation of protein synthesis has been investigated in the reticulocyte-lysate cell-free translation system. Recombinant EBER-1 was synthesized by in vitro transcription of a plasmid containing the viral gene and purified by CF11-cellulose chromatography and ribonuclease III treatment. When added to the reticulocyte lysate at 1020 g/ml or more, EBER-1 prevents the inhibition of protein synthesis caused by low concentrations of synthetic double-stranded RNA, poly(I) · poly(C). This effect is eliminated by treatment of the recombinant EBER-1 with ribonuclease T1. Disruption of the secondary structure of EBER-1 by substitution of inosine for guanosine in the in-vitro -syntheized RNA impairs the ability of EBER-1 to prevent the poly(I) · poly(C)-mediated inhibition of protein synthesis. These results suggest that high concentrations of EBER-1 regulate protein synthesis by blocking the activation of the double-stranded RNA-dependent eukaryotic initiation factor 2± (eIF-2±) protein kinase DAI (p68), and that this property is dependent on the secondary structure of the small RNA molecule.

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