title: A novel autosomal-recessive mutation, whitish chalk-like teeth, resembling amelogenesis imperfecta, maps to rat chromosome 14 corresponding to human 4q21.
abstract: A rat mutant, whitish chalk-like teeth (wct), with white, chalk-like abnormal incisors, was discovered and morphologically and genetically characterized. The mutant rats showed tooth enamel defects that were similar to those of human amelogenesis imperfecta. The wct mutation was found to disturb the morphological transition of ameloblasts from secretory to maturation stages and to induce cyst formation. This mutation also disturbs the transfer of iron into the enamel, resulting in the whitish chalk-like incisors. A genetic linkage study indicated that the wct locus maps to a specific interval of rat chromosome 14 between D14Got13 and D14Wox2. Interestingly, the human chromosomal region orthologous to wct, a 5.5-Mb interval in human chromosome 4q21, is a critical region for the locus of human amelogenesis imperfecta AIH2. These results strongly suggest that this wct mutant is a useful model for the identification of genes responsible for amelogenesis imperfecta and molecular mechanisms of tooth development.
authors.affiliation: Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan. t.masuyama@tba.t-com.ne.jp
authors.forename: Taku
authors.initials: T
authors.lastname: Masuyama
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Miyajima
authors.forename: Hayato
authors.initials: H
authors.lastname: Ohshima
authors.forename: Masaru
authors.initials: M
authors.lastname: Osawa
authors.forename: Norihide
authors.initials: N
authors.lastname: Yokoi
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Oikawa
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Taniguchi
mesh_terms: D000565:Ameloblasts / Q000166:cytology*; D000567:Amelogenesis Imperfecta / Q000235:genetics*; D000818:Animals; D002454:Cell Differentiation; D025063:Chromosome Disorders / Q000235:genetics*; D002874:Chromosome Mapping; D002894:Chromosomes, Human, Pair 4; D004195:Disease Models, Animal; D005260:Female; D005808:Genes, Recessive / Q000235:genetics*; D008040:Genetic Linkage; D006801:Humans; D008297:Male; D051379:Mice; D051381:Rats; D011916:Rats, Inbred F344; D011922:Rats, Mutant Strains / Q000235:genetics*; D017207:Rats, Sprague-Dawley