ChIP-qPCR analysis of in vivo binding of h PARP-1 to the NHE III1 region present in the promoter of the h c-myc gene, and which is presumably either in the GQ form or in the double stranded B-DNA form.

ChIP-qPCR analysis was carried out as described in the Materials and Methods section using a polyclonal antibody raised against PARP-1 (Santa Cruz, H250; 2 µg/extract of one million cells) as precipitation agent. The treatment modalities and the ratio of PARP-1 bound promoter DNAs, isolated from differently treated cells (HeLa and HL60), and amplified by qPCR and calculated from the fluorescence of the Eva-Green complexes formed with the double-stranded PCR products, are shown. The c1/c2 values represent the ratio of the concentrations of PARP-1 bound c-myc promoter DNAs present in the ChIP products obtained from the treated (1) and from the non-treated (2) cell populations and calculated using the c1/c2 = 2n2 – n1 formula, where n1 and n2 are the number of PCR cycles needed to reach the same fluorescence value in the logarithmic phase of the PCR curves.