Possible function of Ah receptor nuclear translocator (Arnt) homodimer in transcriptional regulation.
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.
Sogawa
K
K
Department of Chemistry, Faculty of Science, Tohoku University, Sendai, Japan.
Nakano
R
R
Kobayashi
A
A
Kikuchi
Y
Y
Ohe
N
N
Matsushita
N
N
Fujii-Kuriyama
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D016367:Baculoviridae; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D002522:Chlorocebus aethiops; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004330:Drosophila / Q000378:metabolism; D029721:Drosophila Proteins; D005786:Gene Expression Regulation; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D015151:Immunoblotting; D016350:Leucine Zippers; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000378:metabolism; D056950:Period Circadian Proteins; D014176:Protein Biosynthesis; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D018411:Spodoptera; D014157:Transcription Factors / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection
D000906:Antibodies; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D051792:Basic Helix-Loop-Helix Proteins; D015500:Chloramphenicol O-Acetyltransferase; D004247:DNA; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D056950:Period Circadian Proteins; D018336:Receptors, Aryl Hydrocarbon; D014157:Transcription Factors; C497396:ARNT protein, human; C539040:PER protein, Drosophila; C089449:sim protein, Drosophila