title: Phex mutation causes the reduction of npt2b mRNA in teeth.
abstract: Hyp mice (murine homologue of human X-linked hypophosphatemia) have a disorder in phosphate homeostasis, and display hypomineralization in bones and teeth. We investigated whether a mutation of Phex (phosphate regulating gene homologies to endopeptidase on the X chromosome) has an effect on the expression level of type II sodium-dependent phosphate co-transporter (Npt2) in the developing teeth of the Hyp mouse. Quantitative RT-PCR analyses revealed that the amount of Npt2b mRNA, an isoform of Npt2, in Hyp mouse tooth germs was significantly lower than that in wild-type mice, in both in vivo and in vitro experiments. In addition, tooth germs from wild-type mice cultured in medium supplemented with antisense oligo-deoxynucleotide for Phex also showed a reduction of Npt2b mRNA expression. These findings suggest that the loss of Phex function is related to the defect of Npt2b expression in teeth, and Npt2b reduction is an intrinsic defect of Hyp murine teeth.
authors.affiliation: Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, 1-8, Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Onishi
authors.forename: R
authors.initials: R
authors.lastname: Okawa
authors.forename: T
authors.initials: T
authors.lastname: Ogawa
authors.forename: S
authors.initials: S
authors.lastname: Shintani
authors.forename: T
authors.initials: T
authors.lastname: Ooshima
mesh_terms: D000818:Animals; D001483:Base Sequence; D015536:Down-Regulation; D053098:Familial Hypophosphatemic Rickets / Q000378:metabolism*; D040181:Genetic Diseases, X-Linked; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009805:Odontogenesis / Q000502:physiology*; D009924:Organ Culture Techniques; D053402:PHEX Phosphate Regulating Neutral Endopeptidase / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017384:Sequence Deletion; D050614:Sodium-Phosphate Cotransporter Proteins, Type IIb / Q000096:biosynthesis*; D014083:Tooth Germ / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D050614:Sodium-Phosphate Cotransporter Proteins, Type IIb; D053402:PHEX Phosphate Regulating Neutral Endopeptidase; C506232:Phex protein, mouse