FIG. 7.

Recruitment of HDAC is sufficient for Blimp-1 repression in the Gal4 assay. (A) Expression plasmids encoding Gal4DBD-Blimp-1 fusion protein (Gal4-Blimp-1) or a vector which expresses only Gal4DBD (Control) were cotransfected into 18-81 cells with the (Gal4)₄-tk promoter driving the luciferase gene or tk-Luc (which lacks Gal4DNA binding sites). Where indicated, transfected cells were treated with the HDAC inhibitor TSA at 100 ng/ml after transfection. Cells were harvested 16 h after transfection, and luciferase activities were measured. (B) Ten micrograms of expression plasmid encoding Gal4DBD-Blimp-1 with internal deletions of aa 312 to 492 and aa 557 to 714 (which cannot bind HDAC2; refer to Fig. 5) or Gal4-Blimp-1 containing only aa 557 to 714 (which is sufficient to bind HDAC2; refer to Fig. 5) was cotransfected into 18-81 cells with 2 μg of (Gal4)₄-tkLuc. A plasmid which expresses full-length Blimp-1 fused to Gal4DBD (Gal4-Blimp-1) was used as a positive control, and one which expresses Gal4DBD (Control) was used as a vector control. Transfection results are averages of three or more independent transfections, and error bars show 1 standard deviation from the mean.