Figure 5.

In MEFs, JMJD3 activates both Arf and Ink4a, causing Arf-dependent growth arrest. (A) MEFs were infected with a control vector or with activated RAS. After selection, cells were subjected to ChIP using the indicated antibodies and primer sets (Supplemental Table S1). The approximate location of the primer sets used is shown. (B) In normal MEFs, ectopic expression of JMJD3 or RAS causes up-regulation of both Arf and Ink4a transcripts. (C) Ectopic expression of JMJD3 or RAS in MEFs causes a senescence-like arrest. The top panel shows crystal violet staining at 10–15 d post-infection. The bottom panel shows typical senescence-like morphology. (D) JMJD3 and RAS cause growth arrest in normal and Ink4a^−/− MEFs but not in p53^−/− or Arf^−/− MEFs. Relative cell numbers were assessed by crystal violet staining. The data are representative of between two and six independent experiments for each genotype.