Fig. 3. Gel-shift assays of Int and the C-domain. The indicated amounts of protein were mixed with either 0.1 µM ³²P-labeled synthetic 35 bp COC′ core-type DNA (left panel) or 36 bp P′1,2 arm-type DNA (right panel), as described in Materials and methods. ‘Zero’ lanes indicate the substrate DNA alone. The reaction was analyzed by electrophoresis in 8% polyacrylamide gel.