CBP/p300 functions as a possible transcriptional coactivator of Ah receptor nuclear translocator (Arnt).
A heterodimer of AhR (aryl hydrocarbon receptor) and Arnt (AhR nuclear translocator) conveys a transactivation signal of aromatic hydrocarbons such as 2,3,7,8-tetrachlorodibenzo-p-dioxin and 3-methylcholanthrene to the genes for a group of drug-metabolizing enzymes. This inducible expression of the genes is inhibited by adenovirus E1A, suggesting that CBP/p300 is somehow involved in the transactivation of the genes by the AhR and Arnt heterodimer. Yeast and mammalian two hybrid systems revealed that CBP/p300 interacted with the transactivation domain of Arnt, but not with that of AhR, via the CREB-binding domain. The pull down assay using GST-Arnt hybrid protein confirmed the interaction between Arnt and CBP/p300. Considering these results and that Arnt or Arnt2 functions as a common partner in the formation of transcriptional regulators with other bHLH/PAS proteins such as AhR, HLF, and HIF-1alpha, the possibility arises that CBP/p300 is extensively involved as a coactivator in the transactivation process by bHLH/PAS (a conserved sequence motif among Per, Arnt, and Sim) heterodimer transcription factors through interaction with Arnt or Arnt2.
Kobayashi
A
A
Department of Chemistry, Graduate School of Science, Tohoku University, Sendai.
Numayama-Tsuruta
K
K
Sogawa
K
K
Fujii-Kuriyama
Y
Y
D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins; D051548:Histone Acetyltransferases; D010957:Plasmids; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor
D000123:Acetyltransferases; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D051548:Histone Acetyltransferases; D018336:Receptors, Aryl Hydrocarbon; D015534:Trans-Activators; D014157:Transcription Factors; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor