FIG. 3.

Viral terminal repeat acts to enhance transcription from a promoter upstream of orf73E2. (A) Characterization of the orf73 p2 promoter. Reporter constructs carrying DNA fragments from within the indicated genomic coordinates were generated as described for p1 reporter constructs. For constructs containing the γHV68 terminal repeat, an XcmI fragment containing a single terminal repeat sequence was subcloned into the BamHI site of pGL3. (B) Transfections and luciferase assays were carried out in the same manner as described for p1 promoter constructs in Fig. 2B. Luciferase activity in cells transfected with p2-300-TR or pGL3-TR was plotted in comparison to activity in lysates from cells transfected with the p2-300 construct. (C) The genomic DNA fragments tested in panel B were analyzed for presence of consensus transcription factor binding sites (overlined) as described in the legend to Fig. 2. The splice donor and splice acceptor sites for 73E2 are boxed in white and the sequence of 73E2 is boxed in gray. The 5′ termini identified in S11E lymphoma cells and day 16-infected mouse splenocytes for 73 transcripts containing only 73E2 and 73E3 exons are indicated with solid arrowheads.