Characteristics of 3Cpro-expressing cells. Calu-1/3Cpro culture is shown 72 h p.t. Chromatin was visualized by DNA-intercalating dye Hoechst 33342 (Hoechst channel). Active caspases were detected by fluorescent agent FLICA (FLICA channel). eGFP-positive cells with normal morphology are indicated by cyan arrows. eGFP-positive vacuolated and round cells with condensed chromatin and inactive caspases are indicated by white and green arrows, respectively. eGFP-positive cells with active caspases are indicated by red arrows. Cells demonstrating chromatin condensation and karyorrhexis but not accumulating eGFP are indicated by yellow arrows. eGFP is the channel for GFP fluorescence; Merged channel shows overlapping signals.