Mapping of adenovirus type 5 temperature-sensitive mutations by marker rescue in enhanced double DNA infections.

Adenovirus type 5 DNA has low infectivity (Graham & van der Eb, 1973) which can be increased by various techniques, one of which is the dimethyl sulphoxide (DMSO) boost (Stow & Wilkie, 1976). In this report, it is shown that DMSO treatment of adenovirus 5 DNA-infected HeLa cells results in a 10-fold increase in plaque formation, and that this can be used to facilitate marker rescue experiments. Double DNA infections were performed by the calcium phosphate method, co-precipitating intact temperature-sensitive mutant DNA with purified wild-type DNA restriction endonuclease fragments. Analysis of the plaquing ability of these mixtures and any progeny virus has resulted in the assignment of six temperature-sensitive mutations to discrete physical locations on the adenovirus type 5 genome. These locations are discussed with respect to the mutant phenotypes and the transcription-translation products of the appropriate regions.