Figure 2.

Transrepressing properties of different KRAB domains. (A–F) Increasing amounts of the indicated GAL4 expression plasmids (3, 10, 30, or 100 ng) were transiently transfected into COS-1 cells with 1 μg 17M2-ERE-G-CAT reporter and 1 μg pCH110 (expressing β-galactosidase). The fold repression of each construct was determined by measuring relative CAT activity by using the unfused GAL4 expression vector as a standard. Values (±10%) represent the averages of three independent duplicated transfections after normalization to the internal control β-galactosidase activity of pCH110. Expression of the fusion proteins was confirmed by Western blot by using the antibody 2GV3 against the GAL4 DBD (data not shown).