Selective techniques for the isolation of morphological revertants of sarcoma virus transformed cells

Publisher Summary The isolation and characterization of mutants of viruses that infect bacterial and animal cells has led to increased understanding of viral genetic functions. This approach has been increasingly used in avian and mammalian systems in attempts to determine the number and actions of genes that mediate the transforming activities of oncogenic viruses. The methods used in mammalian systems to obtain virus mutants have usually involved mutagenization of virus, and screening systems have generally been designed to detect conditional lethal effects. DNA and RNA tumor viruses that nonproductively transform and become stably associated with the cell have provided another approach with which to study both viral and cellular genes involved in the expression of viral transformation. Selection systems devised to enhance survival of revertant clones of virus transformed parental cells have yielded both temperature dependent and independent revertants that express normal growth properties in vim and in vivo, and yet still contain the transforming virus. This chapter describes selection techniques that have been developed for the isolation of morphological revertants of tumor virus-transformed cells and characterization of their biological properties. The techniques described here are also applicable to the isolation of revertants of other carcinogen-induced, virus-transformed or spontaneously transformed tumor cells. These MSV transformed nonproducer cell revertants should be of use in developing a better understanding of the virus-cell interactions involved in transformation.