HL-60 cells. ChromaTide BODIPY FL-14-dUTP.
HL-60 cells treated with camptothecin for three hours. The DNA strand nicks characteristic of apoptosis were detected with the TUNEL (terminal deoxynucleotidyl transferase–mediated dUTP nick end-labeling) assay using the fluorescently labeled nucleotide ChromaTide BODIPY FL-14-dUTP (C7614). Image contributed by Zbigniew Darzynkiewicz, Cancer Research Institute, New York Medical College.