9305389 Bujarski The long term goal of this research is to understand the molecular mechanism of RNA-RNA recombination in brome mosaic virus (BMV), a single-stranded positive-sense RNA virus. A unique heteroduplex driven recombination system capable of directing a cross between engineered 3' non-coding region of the mutant BMV RNA-3 and the wild type virus has been developed in our laboratory. We will use this recombination system to study the involvement of BMV replicase proteins in recombination. Effects of mutations in 1a and 2a proteins on the frequency and symmetry of crossovers and on the incorporation of nontemplated nucleotides will be determined. These studies should allow us to map the recombinationally active replicase sequences. %%% These experiments will provide novel insight into an understanding of the basic nature of recombinational events in BMV and other RNA viruses. ***
