Molecular cloning and expression analysis of the aryl hydrocarbon receptor of Xenopus laevis.
The aryl hydrocarbon receptor (AHR) is a member of the basic helix-loop-helix/Per-Arnt-Sim (bHLH/PAS) family of transcription factors. Although this receptor has been known to mediate the toxic effects of environmental pollutants, its physiological functions remain elusive. Here, we describe the isolation and expression pattern of the Xenopus AHR gene. The predicted amino acid sequence contained regions characteristic of other vertebrate AHRs. However, in line with previously described fish AHR genes, no distinct Q-rich domain was found. Phylogenetic analysis demonstrated that Xenopus AHR was clustered within the AHR1 clade. As in the case of mammalian AHR genes, the Xenopus AHR gene was expressed in all the adult tissues tested. Xenopus AHR was also expressed during early development, in parallel with expression of the CYP1A7 gene, which is thought to be regulated by AHR. These results suggest that while frogs are relatively tolerant to TCDD toxicity, the AHR of frogs has characteristics similar to those of other vertebrate AHRs.
Ohi
Hiroaki
H
Laboratory of Biopharmaceutics, School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
Fujita
Yoshiaki
Y
Miyao
Makiko
M
Saguchi
Ken-ichi
K
Murayama
Nobuhiro
N
Higuchi
Shigesada
S
D000595:Amino Acid Sequence; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D003001:Cloning, Molecular; D015870:Gene Expression; D006801:Humans; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000096:biosynthesis; D018336:Receptors, Aryl Hydrocarbon / Q000096:biosynthesis / Q000145:classification / Q000235:genetics*; D016415:Sequence Alignment; D014018:Tissue Distribution; D029867:Xenopus Proteins / Q000096:biosynthesis / Q000235:genetics*; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics* / Q000378:metabolism
D051792:Basic Helix-Loop-Helix Proteins; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; D029867:Xenopus Proteins; C476769:aryl hydrocarbon receptor, Xenopus