enzymatic footprinting uracil interference assay orchard PSI-MI MI:1352 In uracil interference assays, the DNA will be amplified by PCR in the presence of a mixture of TTP and dUTP to randomly replace thymine by deoxyuracil residues before the binding assay. If T nucleotides involved in protein-DNA interactions are replaced by deoxyuracil, protein binding is prevented. After isolating the protein-DNA complex, DNA is cleaved with uracil-N-glycosylase, which specifically targets uracil bases, and the products are electrophoresed on a denaturing polyacrylamide gel. As a result, DNA in which a thymine involved in binding is replaced by uracil will be depleted. Hence, although the pattern looks like a footprint, the blank region means "contact points". 2015-01-28T10:12:25Z