Expression of the mediators of dioxin toxicity, aryl hydrocarbon receptor (AHR) and the AHR nuclear translocator (ARNT), is developmentally regulated in mouse teeth.
Dioxins are persistent and ubiquitous environmental poisons that become enriched in the food chain. Besides being acutely lethal, the most toxic dioxin congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is developmentally toxic to many animal species. We have previously found that developing teeth of children may be sensitive to environmental dioxins via their mother's milk and that rat and mouse teeth are dioxin-sensitive throughout their development. The aryl hydrocarbon receptor (AHR) together with the AHR nuclear translocator (ARNT) protein is believed to mediate the toxic effects of dioxins. To study the potential involvement of the AHR-ARNT pathway in the dental toxicity of TCDD, we analysed the expression of AHR and ARNT by in situ hybridization and immunohistochemistry in developing mouse teeth. AHR mRNA first appeared in the epithelium of E12 first molar tooth buds and both proteins were weakly expressed in the bud. After cytodifferentiation the expression was up regulated and became intense in secretory odontoblasts and ameloblasts. The coexpression of AHR and ARNT during early tooth development as well as during the information and mineralization of the dental matrices is suggestive of the AHR-ARNT pathway as a mediator of dental toxicity of TCDD.
Sahlberg
Carin
C
Department of Pedodontics and Orthodontics, Institute of Dentistry, University of Helsinki, Finland. carin.sahlberg@helsinki.fi
Pohjanvirta
Raimo
R
Gao
Yuguang
Y
Alaluusua
Satu
S
Tuomisto
Jouko
J
Lukinmaa
Pirjo-Liisa
PL
D000818:Animals; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D001483:Base Sequence; D017931:DNA Primers; D004268:DNA-Binding Proteins; D004147:Dioxins / Q000633:toxicity*; D005314:Embryonic and Fetal Development; D017403:In Situ Hybridization; D051379:Mice; D008815:Mice, Inbred Strains; D009805:Odontogenesis / Q000502:physiology*; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
C497397:Arnt protein, mouse; D017931:DNA Primers; D004268:DNA-Binding Proteins; D004147:Dioxins; D000072317:Polychlorinated Dibenzodioxins; D018336:Receptors, Aryl Hydrocarbon; D014157:Transcription Factors; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator