FIG. 8.

In vitro binding analysis of candidate CSL binding sites. Gel mobility shift assays were performed using ³²P-labeled probes containing candidate CSL binding sites from the ORF70 (A), ORF19 (B), and ORF47 (C) promoters. Individual sites are numbered in accordance with Fig. 4, 5, and 6. Characterized binding sites from the EBV Cp promoter (panel A, lanes 1 and 2) and the ORF57 promoter (panel B, lanes 1 and 2) were included as positive controls. All probes were identical in length and were mixed with HeLa whole-cell extract from mock-transfected cells (odd-numbered lanes) or cells expressing tagged CSL (even-numbered lanes). Binding reaction mixtures were incubated at 30°C for 30 min prior to being loaded on a 4% native PAGE gel. Positions of the unbound probe and complexes corresponding to endogenous (CSL) or transfected CSL (rCSL) are indicated. Nonspecific complexes are marked with asterisks.