CDK8 shifts association from mediator to RIP140 during differentiation. A, ChIP/Re-ChIP to monitor endogenous protein complexes associated with RIP140, MED1, and CDK8 on Crabp1 basal promoter on d 0, 4, and 8 of 3T3-L1 differentiation. These ChIP data are quantified as shown in Supplemental Fig. 1 and Supplemental data, published on The Endocrine Society's Journals Online web site at http://mend.endojournals.org. B, Western blot analysis to monitor relevant endogenous protein levels throughout differentiating 3T3-L1 cells. IB, Immunoblot; Cyc C, Cyclin C; Diff., differentiation.