FIG. 4.

EBV genomes associate with specific histone modifications. The localization of different EBV genomes in epigenetic regions was determined with a combination of immunofluorescence techniques. The EBV genome of Raji cells (A) and an LCL transformed with a full-length EBV genome (B) were visualized by FISH using an EBV-specific probe (red). Colocalization with histone 3 trimethylated at lysine 4 (H3K4me3; first panel), histone 3 trimethylated at lysine 9 (H3K9me3; second panel), histone 3 trimethylated at lysine 27 (H3K27me3; third panel), and histone 3 acetylated at lysine 9 (H3K9ac; fourth panel) is shown in green. 3D reconstructions of the Raji cells are shown in Fig. S3 in the supplemental material. Scale bar = 2 μm. (For signal intensity scans of panel A, see Fig. S3 in the supplemental material). (C) ChIP experiments of HEK293 cells transfected with wild-type oriP. Cells were cross-linked for 8 min at room temperature with 1% formaldehyde. Sonicated chromatin (200 μg) was immunoprecipitated with 2.5 μg of the indicated antibody. Coprecipitated DNA was analyzed with oriP-, oriLyt-, and Q-promoter specific primer pairs as described previously (45) and quantified in relation to the amount of the input chromatin (y axis).