FIG. 4.

Expression of eGFP/NS1 induces apoptosis in HepG2 cells. Cells expressing either eGFP/NS1, eGFP/NS1ΔNTP, or eGFP were incubated for 24 h and then stained with annexin V conjugated to Alexa-fluor 594 (red). (A) Apoptotic cells stain red around the border of the cell, while eGFP/NS1 or eGFP is detectable by green fluorescence. (B) Quantification of annexin staining experiments. eGFP/NS1 induces significantly more apoptosis than eGFP alone (P < 0.0006) or than the NTP deletion mutant (P < 0.05).