FIG. 2.
Inactivation of the NRREs in the preC promoter and enhancer I. (A) Sequences of the point mutations introduced into NRREpreC and NRREenhI such that translation of the open reading frames of the X and P genes remains unaffected. The imperfect direct repeats of the NR half-site sequence are boxed. The base pair changes introduced by mutagenesis are shown as underlined lowercase letters. (B) EMSAs used to determine the binding of NRs to wild-type (WT) and mutant NRREs. Radiolabeled double-stranded oligonucleotides containing the wild-type and mutant NRRE sequences were used as probes. DNA-protein complexes are indicated by the bracket; free probes are indicated by the arrow.