Nature and Organization of Retroviral Genes in Animal Cells

l RNA tumor viruses have become increasingly utilized in studies of cellular transformation and gene regulation. The genes of retroviruses exist in two forms; as extrachromosomal, RNA-containing, infectious particles and as DNA pro­ 2 viruses stably associated with cell genes. Components from the extracellular form can be collected in large quantity and purified for the preparation of molec­ ular ...