FIG 4.

RNAi knockdown of Chk1/2 induces cytoplasmic localization of wild-type apoptin. (A) H1299 cells were transfected at low confluence with the indicated siRNA duplexes and allowed to proliferate for 16 h. The cells were then infected with Ad-Apwt and processed for Flag immunofluorescence at 24 h postinfection. (B) Immunoblot analysis of the experiment shown in panel A verifying knockdown efficiency and specificity. (C) Quantification of cells displaying nuclear apoptin was determined by scoring at least 100 Flag-positive cells per condition. **, P ≤ 0.01. NSC indicates a nonsilencing control.