a-c, Endogenous expression of known P53 target genes as measured by qPCR in auxin or/and Nutlin-3a treated MED15- (a, tail module), MED19- (b, middle module) or MED1-AID (c, middle module) cells. Western blot of the denoted Mediator subunit in the respective COF-AID cell line, without and with auxin (IAA) treatment for 3h is shown on top. gel source data: Supplementary Figure 1. d, Endogenous expression of known P53 target genes as measured by qPCR upon Nutlin-3a treatment before and after MED17 (head module) knock-down via RNAi in WT HCT116 cells. e, Endogenous expression of P53 target genes as measured by qPCR in DMSO or Nutlin treated mouse CH12 cells, either wild-type (WT) or knock-out (KO) cell lines for different Mediator subunits (cell lines from ref. 18). Experiment was performed in two batches (shown in two rows), each time using a re-thawed WT cell line as a control. Tailless = quintuple knock-out for MED15, MED16, MED23, MED24 and MED25 subunits. In all panels, N=3 independent replicates; fold-change for each replicate calculated independently by dividing the treatment value with the corresponding control value; mean +/- SD shown; P-values: two-sided Student’s t-test.