Detection of autonomous replicating sequences (ars) in the genome of Epstein-Barr virus.

Epstein-Barr virus (EBV) DNA was analyzed for the presence of autonomous replicating sequences (designated ars) in a eukaryotic system consisting of a uracil auxotroph of Saccharomyces cerevisiae, YNN27, and a pBR322 hybrid plasmid, YIp5, containing the yeast uracil gene but apparently lacking a eukaryotic origin of replication. Cloned EBV DNA EcoRI restriction fragments, A, B, and DIJhet, were judged to function in this capacity by their ability to convert YNN27 cells to the uracil phenotype after transformation with each EBV-specific fragment ligated into YIp5. Additional analyses to confirm and to specify further the location of the ars were performed by cleavage of EcoRI fragments A and B into smaller BamHI fragments, which were subsequently cloned in YIp5 and tested for their ability to function as ars. BamHI fragment X, obtained from EcoRI fragment A, and BamHI fragment R, obtained from EcoRI fragment B, showed ars behavior. The successful recovery of the appropriate virus DNA segments in plasmid form from transformed yeast cells and the ability of these yeast cells to be propagated further substantiated the ars capability of the three EBV fragments.