Possible function of Ah receptor nuclear translocator (Arnt) homodimer in transcriptional regulation.

K Sogawa, R Nakano, A Kobayashi… - Proceedings of the …, 1995 - National Acad Sciences
K Sogawa, R Nakano, A Kobayashi, Y Kikuchi, N Ohe, N Matsushita, Y Fujii-Kuriyama
Proceedings of the National Academy of Sciences, 1995National Acad Sciences
Arnt (Ah receptor nuclear translocator) is a member of a transcription factor family having
characteristic motifs designated bHLH (basic helix-loop-helix) and PAS and was originally
found as a factor forming a complex with Ah receptor (AhR) to bind the specific xenobiotic
responsive element (XRE) sequence for induction of drug-metabolizing P4501A1. We have
examined interaction of Arnt with other PAS proteins--Drosophila Per, Sim, and AhR--by the
coimmunoprecipitation method. Arnt formed a homodimer with itself as well as heterodimers …
Arnt (Ah receptor nuclear translocator) is a member of a transcription factor family having characteristic motifs designated bHLH (basic helix-loop-helix) and PAS and was originally found as a factor forming a complex with Ah receptor (AhR) to bind the specific xenobiotic responsive element (XRE) sequence for induction of drug-metabolizing P4501A1. We have examined interaction of Arnt with other PAS proteins--Drosophila Per, Sim, and AhR--by the coimmunoprecipitation method. Arnt formed a homodimer with itself as well as heterodimers with the others by means of the PAS and HLH domains in a cooperative way. The Arnt homodimer binds the sequence of adenovirus major late promoter (MLP) with the E box core sequence CACGTG, suggesting that the CAC half of the XRE, CACGCN(A/T), recognized by the AhR-Arnt heterodimer is a target for Arnt. Cotransfection experiments using CV-1 cells with an Arnt expression plasmid and a MLP chloramphenicol acetyltransferase (CAT) reporter plasmid revealed that Arnt markedly activated CAT expression, indicative of a newly discovered regulatory role of Arnt.
National Acad Sciences