Investigation on the potential role of the Ah receptor nuclear translocator protein in vitamin D receptor action.
The Ah receptor nuclear translocator protein (ARNT) is required for binding of the Ah (dioxin) receptor to the xenobiotic responsive element (XRE), and is a structural component of the XRE-binding form of the Ah receptor. The vitamin D receptor requires an accessory protein for binding to the vitamin D responsive element (VDRE) in the osteocalcin gene. Since the vitamin D receptor has similarities to the Ah receptor, we investigated whether ARNT is also required for vitamin D receptor activity. Two lines of evidence demonstrate that ARNT is not required for vitamin D receptor activity, and therefore does not correspond to the vitamin D receptor accessory protein: i) Antibodies to ARNT have no effect on binding of the vitamin D receptor to the VDRE. ii) c4, a mutant of Hepa-1 cells that is defective in ARNT activity, and in which binding of the Ah receptor to the XRE does not occur, possesses a vitamin D receptor with full activity for binding the VDRE.
Reisz-Porszasz
S
S
Laboratory of Biomedical and Environmental Sciences, University of California, Los Angeles.
Reyes
H
H
DeLuca
H F
HF
Prahl
J M
JM
Hankinson
O
O
D000818:Animals; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D002467:Cell Nucleus / Q000378:metabolism*; D004268:DNA-Binding Proteins; D011506:Proteins / Q000502:physiology*; D051381:Rats; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism*; D018167:Receptors, Calcitriol / Q000502:physiology*; D014157:Transcription Factors; D014407:Tumor Cells, Cultured
C497398:ARNT protein, rat; D004268:DNA-Binding Proteins; D011506:Proteins; D018336:Receptors, Aryl Hydrocarbon; D018167:Receptors, Calcitriol; D014157:Transcription Factors; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator