Viral DNA Sequences in Adenovirus-transformed Cells

Abstract

Nononcogenic adenovirus 2 (Ad2) and adenovirus 5 (Ad5) are able to transform rodent cells in vitro (Freeman et al. 1967; Williams 1973). Graham et al. (1975) showed that only the left end of the adenoviral genome is necessary for in vitro transformation. However, it appeared that in a number of transformed cell lines additional segments of adenoviral DNA were present (Sambrook et al. 1975b). This observation rendered it rather improbable that a single specific site on the adenoviral genome is involved in the process of integration. The occurrence of different segments of the viral DNA in the transformed cell raises several questions: (1) Are there preferred sites of integration on the host and viral genomes? (2) Are the host and viral sequences involved in integration homologous? (3) How does the pattern of integration of viral sequences vary in different transformed cell lines? (4) Are the patterns of integration stable during...