FIG. 3.

Determination of KSHV genomic copy number in BAC36-infected cells by Southern blot hybridization. BamHI-digested DNAs from 293 cells, BAC36-infected 293 cells, and KSHV-infected BC-1 and BCBL-1 cells were resolved in an agarose gel, transferred to a nylon membrane, and hybridized with KS330, KS631, and vIRF probes. Then 10 μg of DNA from approximately 5 × 10⁵ BC-1 cells containing 2 × 10⁷ to 4 × 10⁷ KSHV genomes was used as the copy number control. Purified BAC36 DNA (15 ng) was also used as a control. β-Actin was used to calibrate any loading differences between cell lines. BAC36-infected 293 cell lines were determined to harbor 1 to 2 copies of BAC36 per cell.