Energy transfer-enhanced chromosome banding. An overview

The conditions necessary for energy transfer-enhanced chromosome banding are described and the results of chromosome staining produced by different energy donor-acceptor dye pairs are presented. Energy donors with A-T binding or fluorescence quantum yield specificity, such as 33258 Hoechst or quinacrine, in combination with energy acceptors with G-C specific binding (e.g., actinomycins) produce enhanced Q banding, with especially prominent Q-bright polymorphisms. Conversely, G-C specific energy donors, such as chromomycin A₃ or 7-aminoactinomycin D, when used with methyl green, as an A-T specific energy acceptor, produce a reverse type banding in which different, putative polymorphic regions are highlighted. Donor fluorescence should be insensitive to quenching by the energy acceptor in chromosomal regions compatible with donor binding and fluorescence but not acceptor binding (e.g., clusters of 10–30 A-T or G-C base pairs). In addition to providing information about the molecular basis of chromosome banding and facilitating the detection of certain chromosome polymorphisms, the methodology described may prove useful in characterizing chromosome rearrangements, such as the Philadelphia chromosome (t(9q;22q)) translocation found in chronic myelogenous leukemia.