Overlapping but unique DNA binding specificities of the Ah receptor and constitutive dioxin-responsive element binding proteins from human keratinocytes.
To understand the relationships between the protein architecture assembled on dioxin-responsive elements (DRE) and transcriptional regulation by dioxin in human keratinocytes, the nuclear DRE-binding proteins from human keratinocytes were identified and characterized. In addition to the aryl hydrocarbon receptor (AHR) complex inducible by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), nuclear extracts from 3 human keratinocyte cell lines also contained one or more proteins that bound specifically to the DRE but whose levels were unaffected by TCDD or by anti-AHR antibody pretreatment. Alteration of a conserved T, within the core DRE sequence needed for transcriptional activation by the AHR complex, did not affect AHR binding but severely affected the ability of the constitutive proteins to bind. These data suggest that the nonidentical interplay of the AHR and constitutive DRE-binding proteins on the DRE is important in the regulation of genes whose expression is controlled by DRE.
Corton
J C
JC
Chemical Industry Institute of Toxicology, Research Triangle Park, NC 27709, USA.
D001483:Base Sequence; D002460:Cell Line; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects / Q000378:metabolism*; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology*; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism*; D012045:Regulatory Sequences, Nucleic Acid
D004268:DNA-Binding Proteins; D015345:Oligonucleotide Probes; D000072317:Polychlorinated Dibenzodioxins; D018336:Receptors, Aryl Hydrocarbon; D004247:DNA