Figure 1

Flow cytometry and flowchart of experiments. (a) GFP-positive (GFP(+)) and GFP-negative (GFP(-)) cells were obtained by flow cytometric sorting (see Materials and methods). GFP-positive cells are ones with high GFP fluorescence while the GFP-negative cells have low GFP fluorescence. GFP fluorescence is shown on the x-axis (log scale) and FL2 (575 nm band pass sensor; to discriminate dead cells, which autofluoresce) on the y-axis (log scale). The GFP-negative (10⁰ to 10²) and GFP-positive (2 × 10² to 4 × 10⁴) cells are boxed in blue. (b) GFP fluorescence is shown on the x-axis (log scale) and the number of cells in each fluorescence class on the y-axis (linear scale). The GFP-negative cells comprise 96% of the total while the GFP-positive cells comprise 2.23% (horizontal bars indicate the cells that fall into each class). A representative fluorescence activated cell sorting (FACS) run is shown. (c) Flowchart of the experiments presented in this study. Protein and RNA levels in the cells were measured by MuDPIT and microarray gene expression profiling, respectively.