FIG. 8.

Competition gel shift assay. (A) Oligonucleotide sequences used in the assay. The SP1 consensus sequences are underlined. The mutant nucleotides are shown in boldface type. (B) Lanes 1, 5, and 9, ³²P-labeled probe only; lanes 2, 6, and 10, labeled probe with 2 μg of nuclear extract prepared from BCBL-1 cells treated with TPA for 24 h; lanes 3, 7, and 11, labeled probe with nuclear extract and 100 ng of unlabeled SP1 oligonucleotide (WT) as a competitor; lanes 4, 8, and 12, labeled probe with nuclear extract and 100 ng of unlabeled SP1 mutant oligonucleotide (M) as a competitor. The SP1 consensus oligonucleotide and K9 promoter domain 1 (D4 to D5) and domain 2 (D8 to D9) were labeled with ³²P and used as probes in lanes 1 to 4, 5 to 8, and 9 to 12, respectively.