SOLID-PHASE TECHNOLOGY IMPROVES COUPLED GEL SHIFT FOOTPRINTING ANALYSIS/

For the analysis of protein-DNA interactions by coupled gel-shift/foot printing, DNA fragments need to be extracted from polyacrylamide gels and subsequently separated on high resolution gels. Due to impurities in the extracted DNA, single nucleotide resolution is frequently not a chieved. We now describe an improved experimental strategy that employ s transient coupling of DNA fragments to a solid support in order to e xtract DNA of high purity quantitatively, rapidly and reliably. As an example, we describe the application of our protocol to the 'in-gel fo otprinting' by copper phenanthroline. The method should also find appl ication to the chemical interference assays.