DNA sequence determinants for binding of transformed Ah receptor to a dioxin-responsive enhancer

We have utilized gel retardation analysis and DNA mutagenesis to examine the specific interaction of transformed guinea pig hepatic cytosolic TCDD-AhR complex with a dioxin-responsive element (DRE). Sequence alignment of the mouse CYPIA1 upstream DREs has identified a common invariant «core» consensus sequence of TNGCGTG flanked by several variable nucleotides. Competitive gel retardation analysis using a series of DRE oligonucleotides containing single or multiple base substitutions has allowed identification of those nucleotides important for TCDD-AhR-DRE complex formation