ChIP assay for in vivo quantification of β-catenin binding to the ABCB1 promoter. (A) RT-qPCR quantification of β-catenin binding in K562 and Lucena cells. DNA amplification was quantified in bound and unbound fractions after normalization with protein A unspecific amplification. Normalized fractions were used to calculate the bound/input ratio. (B) Representative agarose gel - qualitative analysis – of ABCB1 promoter amplification for β-catenin ChIP assay. Input: bound and unbound fractions; B: bound; UB: unbound.