Binding of nuclear proteins in breast cancer cells to32P- rs1271572G DNA probes. Different doses of nuclear proteins isolated from MDA-MB-231 cells were incubated with 32P-rs1271572G probes and the DNA-protein complexes were shown following autoradiography (lanes 1–7). The nuclear proteins isolated from MCF-7, MDA-MB-468, BT-549 and ZR75-30 were incubated with 32P -rs1271572G and the DNA-protein complexes were shown (lane 9–12). When 32Prs1271572T probes were used, no specific DNA-protein binding was observed (lanes 13 and 14). Binding activity of MDA-MB-231 nuclear extracts with 32P-rs1271572G probe was inhibited by cold rs1271572G probes(×50 times higher than 32P labeled probes) (lane 15). The DNA-protein complex was supershifted after further incubating with anti-YY1 antibody in MDA-MB-231 cells (lane 16). Position A indicated the binding complex in the presence of the anti-YY1 antibody. Position B indicated the binding complex of 32Prs1271572G DNA probes with nuclear proteins from the different breast cell lines. Position C indicated free 32P- rs1271572G DNA Probes.