Although fluorescentin situhybridization (FISH) technology has been used extensively for gene mapping and genome analysis (1 -8 ), methods that visualize the interaction of DNA and protein are required to elucidate the functional aspects of the chromosome. By displaying the physical sites of molecular reactions in the highly organized compartments of the nucleus, this methodology provides more specific information on chromatin domain, chromosome, and nuclear position than data generated by other non-in situDNA-protein interaction assays such as gel retardation analysis.
