Figure 2.

Cell death of Drosophila cell transformants expressing either FasC or reaper. (A–D) Time course of cell death. Samples (1 × 10⁵) of the parental Drosophila cells (○) or their transformants (two or three clones) harboring the expression plasmid for either human FasC or Drosophila reaper (filled symbols) were treated with 0.5 mM CuSO₄, and the cell viability was determined by MTT assay. The cell viability is expressed as percentage of the control cells that were cultured for the same periods without CuSO₄. (A) GM2 cells and their transformants harboring the expression plasmid for human FasC. (B) GM2 cells and their transformants harboring the expression plasmid for reaper. (C) Schneider S2 cells and their transformants for human Fas. (D) Schneider S2 cells and their reaper transformants. (E–G) TUNEL staining of dying Schneider cells. The parental S2 cells (E) and their transformants harboring pMT-rpr (F) or pMT-FasC (G) were treated for 18 hr with 0.5 mM CuSO₄, stained with ApopTag, and analyzed by flow cytometry in a FACScan (Becton Dickinson).