FIG. 3.

The CMVm promoter and transcribed CFP regions of the transgene are associated with HP1β, HP1γ, and H3K9me3. Cells mock transfected with pBluescriptII KS(−) (silent, indicated as OFF) or transcriptionally activated by hTet-Off (indicated as ON) were subjected to ChIP assays using antibodies against HP1β, HP1γ, and H3K9me3. The IP DNA and input DNA were analyzed by quantitative real-time PCR. The relative enrichment was determined by normalizing the immunoprecipitation percentage of transgene sequences (CMVm, black bars; CFP, gray bars), defined as the ratio of IP DNA to input DNA, against that of the active β-actin promoter region (white bars). The mean values and standard deviations from three independent experiments are shown.