Analysis of Integrated Viral DNA and Flanking Cellular DNA Sequences in a Rat Cell Line GY1, Transformed by Ad12 Hind III Fragment-G

The nucleotide sequences around the junction sites between the viral transforming gene and cellular DNA in a transformed cell line GY1 were determined. This cell line had been established from a rat cell line 3Y1 by transformation with the adenovirus type 12 DNA fragment （Hind III-G, nucleotide 1 to 2322） encompassing the entire E1A region and the E1B 19 kd （kilodaltons） protein coding region. This particular cell line contains more than one hundred viral copies per haploid genome. Sequence analysis of four independent viral integrates revealed the following features. 1） Viral DNAs were integrated at multiple different sites of cellular chromosomal DNA. 2） Various levels of deletions occurred at both ends of the transfected viral DNA fragment. 3） There was no internal base change such as deletion, insertion or substitution in the viral integrates so far examined. 4） No common and no highly specific sequences exsisted around the viral-cellular junctions. 5） Simple and repeated sequences were often found in cellular sequences adjacent to the left ends of viral DNAs. 6） Except for the short patch type homologies there was no extensive homology between deleted viral sequences and flanking cellular sequences. 7） Possible palindrome structures could be constructed around the viral-cellular junctions as well as parental viral regions corresponding to the junction sites in all of the cases investigated.departmental bulletin pape