The promoter of CYP6B1, a phytochemical-inducible cytochrome P450 from the black swallowtail (Papilio polyxenes) utilizes several elements in addition to the xenobiotic response element to xanthotoxin (XRE-Xan) for basal and xanthotoxin-inducible expression. One of the elements, XRE-AhR, is well known to mediate induction of CYP1A1, a mammalian cytochrome P450, by aryl hydrocarbons via the aryl hydrocarbon receptor (AhR) and its heterodimeric partner, ARNT. To determine if the Drosophila homologues of AhR and ARNT, spineless (ss) and tango (tgo) respectively, have the ability to activate CYP6B1 transcription via the XRE-AhR, ss and tgo expression plasmids were cotransfected with a functional CYP6B1 promoter:CAT fusion construct into Sf9 lepidopteran cells. Coexpression of ss and tgo, which heterodimerize to bind XRE-AhR, enhanced CYP6B1 transcriptional activity significantly above wildtype basal and xanthotoxin-inducible levels. This activation of the CYP6B1 promoter by AhR/ARNT homologues suggests a role for the aryl hydrocarbon regulatory cascade in the detoxification of natural environmental toxins in the diet of herbivorous insects.
Species 1: Lepidoptera Papilionidae Papilio polyxenes (black swallowtail)
Keywords: gene transcription, herbivory
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