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. Author manuscript; available in PMC: 2009 Jun 15.
Published in final edited form as: J Biol Chem. 2008 Dec 19;284(8):5030–5041. doi: 10.1074/jbc.M805871200

FIGURE 2. The effects of USP5 knockdown are p53-dependent.

FIGURE 2

A–D, ARN8 melanoma cells were transfected with non-targeting siRNA (Control) or siRNA targeting USP5 in combination with siRNA complementary to two different sequences in p53. Where appropriate, total siRNA levels were maintained constant by the addition of non-targeting siRNA. The increases in Mdm2 protein expression (A), p53-responsive transcriptional reporter activity (B), Mdm2 P2 mRNA (C), and p21 mRNA levels (D) are attenuated by p53 knockdown. β-Galactosidase and mRNA levels were normalized to total protein and actin mRNA, respectively, and expressed as a percentage of control (non-targeting siRNA). The values are the means ± S.D. of three experiments. E and F, HCT116 p53+/+ or HCT116 p53−/− cells were mock-transfected (−) or transfected with the indicated siRNA. E, knockdown of USP5 increases p53 and Mdm2 protein levels in HCT116 p53+/+ cells but has no effect on Mdm2 levels in HCT116 p53−/− cells. F, knockdown of USP5 increases Mdm2 P2 mRNA expression in HCT116 p53+/+ cells but not in HCT116 p53−/− cells. mRNA levels were normalized to TBP and expressed as a percentage of control (non-targeting siRNA). The values are the means ± S.D. of three experiments.