Size heterogeneity of EBV and mitochondrial DNAs in Burkitt's lymphoma lines.

A simple, reproducible affinity chromatography method has been adapted for separation of high molecular weight supercoiled circular molecules from mammalian cells. Electron microscopic analysis of EB viral DNA obtained by this method, from the non-producer Burkitt's lymphoma line Raji, revealed monomer-sized viral molecules only. In contrast, the EB viral episomes from recently established human producer lines BL-8 and LY91 were very heterogeneous in size, some being considerably smaller and others much larger than the monomeric DNA. The former are probably related to defective viral species in the B-cell population, but the origin of the latter are as yet unclear. All cell lines contained both monomers and concatemers of mitochondrial DNA; among the latter, molecules apparently greater than 100 kb were observed in the population.