A U2OS cells were transfected with indicated siRNAs, cultivated for 3 days and immunostained for nucleolin (NCL), fibrillarin (FIB) and p53. Bar, 10 μM. B U2OS cells were transfected with indicated siRNAs, cultivated for 3 days and cell lysates analyzed by immunoblotting with indicated antibodies. C U2OS cells were transfected with control or WDR75 siRNAs. Cell lysates were immunoprecipitated 72 h after transfection with control (IgG) or RPL5 antibodies and immunoblotted with indicated antibodies. D U2OS cells were transfected with indicated siRNAs, cultivated for 6 days and stained for senescence-associated β-galactosidase activity. Numbers indicate percentage of cells positive for senescence-associated β-galactosidase activity. Bar, 10 μM.