Localization of integrated operator repeats containing no transcription units after cotransfection with gfplacI- and CMV IE1-expressing plasmids. Components labeled are indicated in the upper corners of the panels with their respective colors. HEp-2-Op cells were cotransfected with pgfplacI and pIE1 for 24 hours, and then the cells were stained blue for IE1 (C) and red for PML (D). The lac Operator/GFP-lac repressor complexes are shown in green (B). All colors are merged in (A).