FIG. 3.

SV40 regulatory region rearrangements detected in hamster tumors. (A) Schematic representation of the SV40 reference strain [776(2E)] showing segments within the regulatory region. ori, origin of DNA replication; G/C, G/C-rich region; 72, 72-bp enhancer element; MLP(+1), major late promoter start site. Numbers above or below the figure identify specific nucleotide positions in 776(2E). The relative borders of specific regulatory region segments are indicated by arrows above or below the figure. Tandemly repeated sequences are depicted by white boxes inscribed with the numbers 21 or 72. (B to E) Regulatory region structures of viruses inoculated (top row) and sequences recovered (bottom row) from hamster tumors. In the tumor induced by 776(1E) in hamster 1263, only the rearranged regulatory region was detected; the original structure was not detected. In tumors from hamsters 1721, 1713, and 982, both original and rearranged regulatory region sequences were detected.