FIGURE 6.

Double knockdown of CDK8 and CDK19 caused PRMT5 and DNMT3A dissociation from C/EBPβ target gene promoters. A and B, occupancies of CDK8/19, PRMT5, and DNMT3A on IL-8 (A) and TNFα (B) genes. To knock down protein expression of Mediator CDKs, an siRNA mixture targeting both CDK8 and CDK19 (CDK8+CDK19) or NC siRNA was transfected into HeLa S3 cells, and occupancies were measured by ChIP followed by qPCR. P, promoter regions; E, exonic regions. Immunoprecipitations were carried out individually three times (n = 3). The data were normalized by defining the signal level in the presence of NC siRNA as 1. The error bars show S.D. *, p < 0.05; **, p < 0.01. C, the efficiency of the CDK8 and CDK19 double knockdown was verified by Western blotting. Lane 1, nontarget control (NC); lane 2, siRNA mixture against both CDK8 and CDK19 (CDK8+CDK19). γ-Tubulin was used as a loading control.