FIG 6.

Regeneration of a DISC GP85 GPCMV from GP85 BAC mutants requires a TRE promoter and a cell line expressing a Tet-Off transactivator (tTA2). (A to C) GP85 mutant GPCMV BACs were individually transfected into GPL cells: GP85/GP86 KmR (A), GP85/86 KmR poly(A) (B), and TRE GP85 DISC (C). (D) Mutants were also transfected onto GPL Tet-Off cells. The TRE GP85 DISC is shown. Individual transfected cells expressed GFP encoded by the BAC. Virus spread was detected by GFP spread across the cell monolayer. Images were taken at 16 days posttransfection.