Chromatin immunoprecipitation assay performed on MCF7, and MDA-MB231 breast cancer cell lines to evaluate in vivo Sp1 binding. Proteins were cross-linked to the DNA with formaldehyde and Abs directed against RNA-Pol (Ab control) or Sp1 were added to precipitate any protein-DNA complexes. The control + lane was DNA that had been sonicated and pre-cleared with protein G beads. The control-lanes were processed according to the protocol, but did not have any Ab added to the samples. PCR were performed on isolated DNA using primers encompassing MsrB1 promoter region -169 to +76. A schematic map of the amplified DNA fragment (245 bp) containing Sp1 binding motifs and TSS position is illustrated as well.