Biophysical evidence for linkage of adenovirus and SV40 DNA's in adenovirus 7-SV40 hybrid particles.

Abstract

The native and alkali- denatured DNA''s of purified hybrid virus E46+ and its antecedents adenovirus 7 and SV40 were subjected to fixed- angle density gradient centrif ugation. The resulting gradient fractions were analyzed for the presence of DNA components hybridizable with adenovirus andSV40 cRNA. The SV40 and adenovirus DNA''s of the hybrid virus were nondissociable while those in a mixture of adenovirus and SV40 were completely dissociable. These findings indicate that the DNA''s of E46+ are linked by an alkali-stable bond as a single molecule within the hybrid particle and that this particle may be aptly termed a hybrid on biophysical grounds. Centrifugation of alkali-denatured Ad. 7DNA yielded two peaks of DNA of different density. The lower density species hybridized preferentially with in vitro cRNA while the denser species, composing the bulk of the DNA, and consisting of denatured strands, hybridized preferentially with RNA extracted from Ad. 7-infected tissue culture cells. The SV40 DNA of E46+ was associated with the denser of these two species.