Fluorescence lifetimes and FRET efficiencies for cells expressing eGFP or NCp7-eGFP in the presence of Sytox Orange.

The lifetime values were extracted from FLIM color coded images such as in Fig. 2, and given as mean +/- SD for 10–13 cells. FRET efficiencies were calculated by comparison with the lifetimes of NCp7-eGFP in the corresponding cell compartments. The SD for the FRET values is about 2%. Cells were fixed with 4% PFA and permeabilized with 1% saponin, as described in Materials and Methods.Fluorescence lifetimes and FRET efficiencies for cells expressing eGFP or NCp7-eGFP in the presence of Sytox Orange.