EMSA assay. Lane 1) Biotin-labled rDNA probe. Lane 2) Biotin-labled rDNA probe + nuclear protein. Lane 3) Biotin-labled rDNA probe + nuclear protein + 100-fold molar excess of biotin-unlabeled specific competitor. Lane 4) Biotin-labled rDNA probe + nuclear protein + 100-fold molar excess of biotin-unlabeled mutant competitor. Lane 5) Biotin-labled rDNA probe + nuclear protein + NF90 antibody. Lane 6) Biotin-labled rDNA probe + nuclear protein + NF45 antibody. The details were described in Materials and Methods section. 