Figure 2. iRFP as a marker for cell number in vitro. Doubling dilution of U2OS (A), HeLa (B), and parental or cMyc/Ha-RasG12V-transformed 3T3 cells (C) stably expressing iRFP. Cells were seeded in 96-well plates at the indicated numbers by doubling dilutions. After 8 h, plates were scanned (left) the iRFP signal determined and and plotted against cell number. Error bars indicate SEM of 12 (A and B) or 6 (C) replicate wells.