Fig. 7.

CDK8 facilitates repression of Crabp1 gene. A, qPCR monitoring Crabp1 mRNA levels under silencing of CDK8 in differentiated 3T3-L1. B, Co-IP of RIP140 complex with G9a in differentiated 3T3-L1 under silencing of CDK8. C, ChIP of GC box region under silencing of CDK8. D, CDK8 silencing efficiency in differentiated 3T3-L1 cells. E, A mechanism model. In predifferentiated cultures, T₃ initially activates Crabp1 gene expression. MED1 maintains juxtaposed chromatin conformation between the distal TRE region and GC boxes and associates with coactivators and CDK8 module. During differentiation, RIP140 is increasingly expressed and acetylated. Acetylated RIP140 replaces MED1 on the Crabp1 promoter and maintains juxtaposed chromatin conformation while recruiting other repressive cofactors, such as G9a through the CDK8 submodule, which is constitutively associated with the Crabp1 promoter. Diff., Differentiation; IB, immunoblot; sc, scramble RNA; si, silencing RNA.