FIG. 4.

mSin3A mediates repression of CIITA transactivation function. (A) COS 7 cells were cotransfected with 100 ng of CIITA, increasing amounts of mSin3A, and 0.5 μg of DRA-luciferase reporter. Luciferase activity is reported as percent activation relative to that by CIITA alone. (B) NcoR is not required for repression of MHC-II promoter activity. Transfection was performed as described for panel A. Values are shown as mean percent relative luciferase activity ± standard error of the mean for three experiments, each of which was repeated in triplicate.