FIG. 6.

Gag-Gag interactions are observed by FRET at intracellular locations. Gag-CFP and Gag-YFP were coexpressed in Mel JuSo cells and imaged by confocal microscopy. (A) Four separate intracellular punctate regions were analyzed for Gag-Gag FRET. The image shown is for YFP excitation (514 nm) and emission. (B) One intracellular region (arrow) was selected from a cell expressing Gag-YFP and Gag-CFP and analyzed for three-dimensional localization within the cell. Image acquisition was optimized for YFP. (C) Emission spectral scans for each region shown in panel A following data collection with CFP excitation (458-nm laser) and multichannel spectral scanning of the regions of interest. (D) Spectral data from z-section optical slices taken starting from the bottom of the cell (section 1) and proceeding to the top of the cell shown in panel B. Data were collected following excitation with a 458-nm laser and multichannel spectral scanning. Note that sections 2 and 3 demonstrate FRET (YFP peak emission) and are internal optical slices.