FIG. 4.

(A) Schematic diagram of EBV promoter in pHEBo-luc, with or without ori lyt. Late promoters were those for BcLF1, BdRF1, and BFRFC) Similar plasmids were made with the promoter for BMRF1 (delayed early) and the Cp latent promoter. (B) Luciferase reporter assays following anti-Ig induction of late promoter luciferase plasmids in AK2003 cells, with or without PAA treatment (0.85 mM). The Western blot assay of the BdRF1 protein demonstrates inhibition of the late lytic cycle by PAA and timing of BdRF1 expression. PCNA was also blotted as a loading control. kRLU, 10³ relative light units; p.i., postinfection. (C) Southern blotting of 2 μg of EcoRI-digested total DNA from AK2003 cells containing the promoter for BdRF1 with no ori lyt or with the core ori lyt or the big ori lyt. The probe was an equal mixture of the B95-8 EcoRI I fragment (for EBV) and the pGL2 vector (Promega) for the luciferase plasmid, labeled by random priming. Restriction fragments corresponding to the endogenous (endog.) EBV or the pHEBo plasmid are shown above an ethidium bromide stain of the DNA on the gel as a loading control.