Restructured transactivation domain in hamster AH receptor.
Hamsters and Han/Wistar (Kuopio; H/W) rats show peculiarly selective responsiveness to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). They are extremely resistant to its acute lethality but sensitive to, e.g. , enzyme induction. The biological effects of TCDD are mediated by the AH receptor (AHR). Recent studies on H/W rat AHR discovered a remodelled transactivation domain which appears to be critical for the TCDD resistance of these animals. Here, molecular cloning and sequencing of hamster AHR reveals another type of restructured transactivation domain. In hamsters, the functionally pivotal Q-rich region is substantially expanded and enriched in glutamine compared with all other AHRs cloned to date. By contrast, the amino-terminal end is highly conserved, which is in agreement with the H/W rat AHR. Because of the additional material in the transactivation domain, hamster AHR protein is larger than that in rats or mice, but the pattern of AHR mRNA expression in tissues is similar.
Korkalainen
M
M
Laboratory of Toxicology, National Public Health Institute, Kuopio, FIN-70701, Finland.
Tuomisto
J
J
Pohjanvirta
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D006224:Cricetinae; D004351:Drug Resistance; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D008647:Mesocricetus; D008969:Molecular Sequence Data; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D018336:Receptors, Aryl Hydrocarbon / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D013045:Species Specificity; D015533:Transcriptional Activation
D000072317:Polychlorinated Dibenzodioxins; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon