FIG. 4.

Effect of regions of MBD1 on transcription when tethered to the DNA by a GAL4 DNA binding domain. (A) Map of reporters with five GAL4 binding sites (G5) and no GAL4 binding sites (G0) and of the effectors which express a fusion between the GAL4 binding site and regions of MBD1 downstream. Effector proteins were expressed from a CMV promoter. (B) Examples of the relative transcription levels of G5 (squares) and G0 (circles) reporters in the presence of increasing amounts of different GAL4-MBD1 effectors. The MBD1(273–340) profile was obtained with effector constructs that contained the second CxxC domain, whereas the MBD1(506–538) profile was obtained with effectors containing the C terminus of MBD1. The shaded box next to each panel provides a key to the repression profile obtained with the effector constructs listed in panel C. (C) Summary maps showing regions in MBD1 that can affect the transcription of reporters in the above assay. Repression characteristic of the CxxC domain [see MBD1(273–340) above] was seen with grey constructs, whereas repression characteristic of the C terminus [see MBD1(506–538) above] was seen with diagonally shaded constructs. aa, amino acids.