Figure 4.
ZNF313 destabilizes CIP/KIP proteins and blocks p21WAF1-mediated cellular senescence. (a) ZNF313 depletion leads to elevation of p21WAF1 but not of p16INK4A protein level. (b) ZNF313 downregulates CIP/KIP but not INK4 family members. (c) A dose-associated elevation of p21WAF1, p27KIP1 and p57KIP2 protein level by siZNF313 transfection. (d) No effect of ZNF313 on cellular senescence of p21WAF1-deficient cells and the recovery of its effect in p21WAF1-restored cells. Senescence-associated (SA)-β-gal assay was performed 5 days after adriamycin treatment (0.5 μg/ml, 2 h). Data represent means of triplicate assays (bars, S.D.) (*P<0.05). (e) No effect of ZNF313 depletion on irradiation-induced G1 cell cycle arrest in p21WAF1-deficient cells. (f) A p21WAF1-dependent effect of ZNF313 on colony formation of tumor cells. HCT116 and its p21−/− subline were transfected with siZNF313 and its effect on colony-forming ability was compared (**P<0.01)