Fig. 6. (A,B) Two fields of YFP fluorescence of SV80 cells transfected with YFP-dSH2. (C,D) Anti-PY staining of the corresponding fields. Images A-D show the fluorescence intensities represented in a spectrum scale, as indicated in the calibration bars. (E,F) Ratio images of the cells shown in (A,C) and (B,D), respectively, depicting the relative fluorescence of PY and YFP-dSH2. The cells shown are numbered consecutively from 1-6. Note the uniform ratio between the two labels in YFP-dSH2 expressing cells (1, 4 and 5), indicating strong correlation between YFP-dSH2 and PY. The cells (2, 3 and 6) showing red FAs (i.e. excess PY) are not expressing detectable levels of YFP-dSH2. (G) Plot of intensity of PY staining against the intensity of labeling in YFP-dSH2-overexpressing cells 1 and 4. (H) Similar plot, as in G, for nonexpressing cells 2, 3, 6, and YFP-dSH2 expressing cell 5. FAs from field 1 are represented in red, whereas FAs from field 2 are represented in black. Notice the linear correlation between the two labels, the increase in PY labeling upon expression of particularly high levels of YFP-dSH2, and the normal PY levels in the moderately transfected cell. Bar, 10 µm.