FIG. 6.

Ku80C inhibits transcription in vivo. Ku80-HA and Ku80C-HA were expressed in HCT116 cells under the control of a CMV promoter. At 48 h posttransfection, cells were incubated with BrU for 1 h to label nascent RNA, fixed, and stained with anti-HA (rat MAb; Roche) and anti-BrU (MAb; Roche), as well as with species-specific secondary antibodies. (A) Transfection with Ku80-HA vector. Each field shows a confocal section with nuclei of three or more cells. Areas of overlap between Ku80-HA and BrU signals appear yellow in the merged image (right panels). Panel B is the same as panel A, except that transfection was with Ku80C-HA vector. Size bar, 2 μm. The experiment was repeated three times with 200 to 400 cells examined each time. Results are representative.