Figure 5.

USP42 depletion delays activation of several p53 target genes in response to stress. (A) U2OS cells were transfected with siRNAs against USP42 or non-targeting siRNA. Cells were treated for the indicated time with 5 nM actinomycin D to activate p53. mRNA expression of the indicated genes was then determined by qRT–PCR with specific primers; mRNA variation rate indicates the percentage activation or repression of expression of each gene compared with control. The results were normalized against two different standard genes and the graphs represent the mean of three independent experiments. (B) U2OS cells treated as in (A) were fixed and chromatin was immunoprecipitated with an antibody against p53. p53 bound DNA was then analysed by qPCR with specific primer amplifying the indicated region of the p21 gene. The results are expressed as a percentage of input and the mean of three experiments.