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.
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - 1995 Mar 14|
- PAS domain
- basic helix-loop-helix domain
ASJC Scopus subject areas