Localization of Halo-p300 with different expression levels. (A and B) Fluorescence images of Halo-p300 and RNAP2 Ser2ph-mintbody expressed in HeLa cells were acquired using a confocal microscope. Cells with low to modest (A) and high (B) expression are shown. Images of Halo-p300 are shown with fixed contrast adjusted to the highly expressed one (top; range, 94–1,445) and with individually adjusted contrast (middle; range indicated). Net nuclear fluorescence intensities, after subtracting background intensities from mean nuclear intensities, are indicated on top. The CCFs to RNAP2 Ser2ph-mintbody are shown at the bottom. Cells with larger Halo-p300 foci (B) were excluded from our analysis. Scale bars, 5 µm.