FIG. 1.

Quantitation of apoptosis using bicistronic vectors coexpressing Nef and GFP. Flow cytometric analysis of uninduced (A to C) or 20-s UV light-treated (D and E) Jurkat cells transfected with constructs expressing GFP alone (B and D) or together with the NL4-3 Nef (C and E). Live cells were selected by forward and side scattering (panel 1). GFP expression allowed us to discriminate between transfected and untransfected cells (panel 2). GFP-positive cells and mock-transfected cells were evaluated for annexin V binding (panel 3), and triple staining for 7-AAD allowed us to distinguish between early and late apoptotic cells (panel 4). Numbers are the percentages of annexin V- and 7-AAD-positive cells. Similar results were obtained in three independent experiments.