Expression of DUSP1, p21, and NOXA in UV- and doxorubicin-treated cells. Mouse DJ-1+/+ cells were treated with 20 J/m2 UV irradiation (A and C) or 1 μM doxorubicin (B an D) for 0.5 to 6 h. The expression levels of mRNA and protein of DUSP1, p21, and NOXA were examined by semiquantitative RT-PCR (A and B) and by Western blotting (C and D), respectively.