10 Supplement

Abstract

During the last year or two, principally because of the widespread application of Southern hybridization and the advent of molecular cloning, there have been considerable advances in knowledge of the organization of viral DNA integrated into the genomes of adenovirus-transformed cells. The major findings are described below.

First, semipermissive cells transformed by adenoviruses (e.g., rat cells transformed by adenovirus 2) often carry multiple sets of partial copies of viral DNA that are not colinear with the viral genome. The best-studied example is the cell line F4 (Gallimore 1974), where the integrated viral DNA, isolated by molecular cloning, has been analyzed by a variety of hybridization techniques and direct DNA sequencing (J. Sambrook and R. Greene, unpubl.). The general structure of the integrated sequences is shown in Figure S10.1. Starting from an EcoRI site on the left, there occurs, in order, a tract of highly repetitive DNA about 1 kb long and a tract of viral sequences 1543 nucleotides long, which begins 2 nucleotides from the right-hand end of the viral genome and extends through part of early region 4 to nucleotide 1545. These right-end sequences are then joined directly to sequences from the left end of the viral DNA by a blunt-end joint. There then follows a tract of sequences approximately 22 kb in length that are colinear with the viral genome as far as map position 63. They therefore include not only the transforming region (early regions 1A and 1B), but also a sizable chunk of late genes. Finally...