Fig 7.

Recruitment of p53 to the Mdm2 promoter in vivo requires MdmX. A chromatin immunoprecipitation (ChIP) assay was performed. MCF7 cells were transfected with control (Luc) siRNA or MdmX siRNA for 48 h. The cells were then treated with NCS for 90 min and subjected to the ChIP protocol as described in Materials and Methods. noAb cont, no-antibody control. (A) ChIP-enriched DNA was quantitated by real-time PCR with primers amplifying Mdm2 P2 promoter (top panel) or p21 5′ RE (bottom). (B) Immunoblot of input material in a typical experiment using antibodies against Mdm2, MdmX, p53, p21, and actin as indicated.