FIG. 3.

Oct4-expressing hESCs can be identified and isolated by FRET-based fluorescence-activated cell sorting (FACS). Typical FACS histograms of proliferating hESCs transfected with 6FAM (donor)- and 5ROX (acceptor)-labeled, Oct4-specific molecular beacons separately and in combination are shown. Flow cytometry detects fluorescence of individual beacons at appropriate wavelengths (6FAM, upper middle; 5ROX, lower left), with absence of overlapping emissions (6FAM, lower middle; 5ROX, upper right). Flow cytometry detects fluorescence at the acceptor's wavelength (610 nm) with excitation of the donor (488 nm) only in cells transfected with both beacons (6FAM+5ROX, lower right). Color images available online at www.liebertonline.com/scd.