A fluorescence energy transfer system for studying the functional properties of chromatin

3YI-B-1 rat embryo fibroblasts were used for double fluorescent labeling. The labeling was carried out with fluorescamine and ethidium bromide as an energy donor-acceptor pair. The fluorimetric measurements proved the existence of an energy transfer process. The parameters of this transfer depended on both cell and dye concentrations. It is this character that makes this labeling technique promising as a means of distinction between cells with different structures.