Recombinant KSHV. (A) Top, schematic diagram of the KSHV genome (). Bottom, components of pQ152, which was used to construct recombinant virus. An expanded segment of the KSHV genome shows the 4.8-kb BamHI fragment containing ORFs 57 and K9. This fragment was used for the insertion of the GFP/Neo cassette between the polyadenylation sites for ORFs 57 and K9. (B) Photomicrographs of BCBL-1 cells that were transfected with pQ152 and grown with G418 selection to generate recombinant rKSHV.152 virus 5 weeks postelectroporation (×100). Panel 1, phase contrast; panel 2, fluorescence. (C) Hybridization analysis, following gel electrophoresis, of DNA isolated from BCBL-1, and BCBL-1 with rKSHV.152, digested with BamHI, HindIII, or PstI. Left panel: analysis with the 4.8-kb BamHI fragment labeled with 32P as a probe. Right panel: analysis of BCBL-1 with rKSHV.152 with the GFP/Neo construct labeled with 32P used as a probe. B, BamHI; H, HindIII; P, PstI. Fragment sizes predicted from the BC-1 sequence () are as follows: BamHI, 4,774 bp; HindIII, 2,030 and 3,001 bp; and PstI, 5,907 bp. The predicted bands from a correct recombination event with the addition of the 2.7-kb GFP/Neo cassette are marked by an (∗). (D) Hybridization analysis of DNA isolated from HF infected with rKSHV.152 following digestion with BamHI, HindIII, or PstI and gel electrophoresis. Left panel: autoradiogram of HF/rKSHV.152 DNA hybridized with the 32P-labeled KSHV BamHI 4.8-kb fragment. Right panel: autoradiogram of HF/rKSHV.152 DNA hybridized with the 32P-labeled GFP/Neo as a probe. B, BamHI; H, HindIII; P, PstI. Fragment sizes expected for a correct recombination event would be 7.5 kb for BamHI, 5.7 kb for HindIII, and 8.6 kb for PstI, based on the published sequence of BC-1(). (E) 293 cells inoculated with virus isolated from BCGL-1 cells containing rKSHV.152. Infected 293 cells were examined for GFP expression and the expression of ORF 59 protein using the MAb 11D1 visualized with Alexa 594 (red). Shown are photomicrographs of infected 293 cells 2 dpi (×100). Panel 1, phase contrast; panel 2, fluorescence with filters for GFP; panel 3, fluorescence with filters for Alexa 594 (red); panel 4, merged image from the green and red filters.