FIG. 3.

Visualization of Gag-Gag FRET by confocal microscopy. Gag-CFP and Gag-YFP were cotransfected in Mel JuSo cells, and images were obtained with a Zeiss LSM 510 confocal microscope equipped with a Meta multichannel detector. Fluorescence excitation was carried out at 458 nm; emission images prepared by linear unmixing techniques for CFP (left panels) and YFP (right panels) are shown. (A) CFP emission image demonstrating weak membrane fluorescence in the indicated region before photobleaching. (B) FRET image indicating efficient plasma membrane Gag-Gag FRET prior to photobleaching of YFP. (C) CFP emission image following photobleaching of YFP in the circled region. Note the increase in CFP emission following YFP photobleaching within the indicated region. (D) FRET image following photobleaching of the indicated area of the cell.