Identification of amber and ochre mutants of the human virus Ad2+ND1.

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Abstract
Although human adenoviruses grow poorly in monkey cells, this defect can be overcome by coinfection of cells with SV-40 or by insertion of the relevant portion of the SV-40 genome into the adenovirus genome to form an adenovirus SV-40 hybrid virus. The nondefective adenovirus-2-SV-40 hybrid virus, Ad2+ND1, contains an insertion of 17% of the SV-40 genome, which codes for at least part of a 30,000 dalton protein. A set of Ad2+ND1 host-range mutants that lost the ability to grow in monkey cells and behave as point mutants fail to synthesize the 30,000 dalton ND1 protein. Translation in vitro of SV-40-specific mRNA from mutant-infected [human oral carcinoma KB and cervical carcinoma HeLa] cells produces unique short polypeptides instead of the 30,000 dalton protein. This set of host-range mutants includes ochre and amber nonsense mutations. When the SV-40-specific mRNA from the host-range mutants is translated in vitro to produce the polypeptide fragments, yeast suppressor tRNA can partially restore synthesis of wild-type-size 30,000 dalton protein. By this assay, 1 mutant is ochre and 2 are amber.