Detection of the presence of Sp1 and Sp3 on the uPA GC-/GA-rich region by chromatin immunoprecipitation assay.

Purified DNA from immunoprecipitated, cross-linked chromatin was amplified by conventional PCR and analyzed as described in “Materials and methods.” The PCR reaction produces a 528-bp band, as indicated on the left. For each sample (α-Sp1, mock, input, and α-uPAR = unrelated Ab), the stock DNA was amplified by PCR together with 3 decreasing dilutions as indicated by the triangles at the top and described in “Materials and methods.” (A) Sp1 is present in the region of the proximal promoter in PC3 cells but not in HeLa cells. (B) Amplification of an Sp1 unrelated region does not show a detectable signal either from HeLa cell– or PC3 cell–derived genomic DNA.