FIG. 2.
Autoradiogram of Southern blot hybridizations of wild-type and recombinant viral DNA fragments. Viral DNAs were isolated, digested with the restriction endonuclease BsrGI, and then subjected to electrophoresis followed by blotting and hybridization with 32P-labeled DNA probes as described in Materials and Methods. A shuttle DNA vector containing the gpt gene with the R1 and R2 elements upstream of the US3 promoter and the CAT gene was used as a hybridization control. (A) Maps of wild-type and recombinant viruses. Locations of the R2 and R1 elements and sizes of the DNA fragments after restriction endonuclease digestion with BsrGI are indicated. The × indicates an interruption of the US3 ORF. (B) Southern blot hybridization with the 32P-labeled CAT, US7, or gpt DNA probe.