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

(A) Gel mobility shift assays using oligonucleotides corresponding to the ankyrin-1 promoter footprinted GATA-1 site or control GATA-1 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 GATA-1 site or a control GATA-1 site were added to the reactions as competitor where indicated. (B) Gel mobility shift assays using oligonucleotides corresponding to the ankyrin-1 promoter footprinted GATA-1 site or control GATA-1 site and K562 cell nuclear extracts. GATA-1 antibody was added to the reaction mixtures where indicated.