Fig 9.

The effects of transfecting the caspase-3-expressing plasmid pcasp3-Wt-GFP into ORF50ΔSTAD BCBL-1 cells were assessed using confocal microscopy. ORF50ΔSTAD BCBL-1 cells were transfected with either the negative-control plasmid pUC19 or pcasp3-Wt-GFP, which expresses functional wild-type caspase-3 as a fusion protein with GFP, and various chemical inducers. Nuclei are stained blue with DAPI, the KSHV late gene ORF K8.1 is stained red, Annexin V is stained magenta, and GFP is shown as green. TPA was given to induce KSHV replication via the orthodox pathway, a low concentration of DOX was given to induce expression of the DN ORF50DSTAD, and DCPE was given to induce apoptosis in the following combinations. The cells were treated with pUC19 alone (A), pUC19 plus DOX (B), pUC19 plus TPA (C), pUC19 plus TPA plus DOX (D), pUC19 plus TPA plus DOX plus DCPE (E), and pcasp3-Wt-GFP (F), The pcasp3-Wt-GFP lead induces both apoptosis and KSHV gene expression, indicating that the end effector caspase-3 is sufficient to induce KSHV replication.