Electrophoretic mobility shift assays of the footprinted Sp1 site in the human ankyrin-1 gene promoter.

(A) Gel mobility shift assays using oligonucleotides corresponding to the ankyrin-1 promoter footprinted Sp1 site or control Sp1 site and nuclear extracts from erythroid (K562) cells. Increasing amounts of unlabeled, DS oligonucleotide (10 molar and 100 molar excess) corresponding to the ankyrin-1 Sp1 site or a control Sp1 site were added to the reactions as competitor where indicated. (B) Gel mobility shift assays using ankyrin-1 promoter oligonucleotides corresponding to the footprinted CACCC site and K562 cell nuclear extracts. Increasing amounts of unlabeled, DS oligonucleotide corresponding to the ankyrin-1 CACCC site, a control CACCC site (10 molar and 100 molar excess), and a control Sp1 site (100 molar excess) were added to the reactions as competitor where indicated. (C) Gel mobility shift assays using oligonucleotides corresponding to the ankyrin-1 promoter footprinted Sp1 site or control Sp1 site and K562 cell nuclear extracts. Sp1 antibody was added to the reaction mixtures where indicated.