title: R-spondins/Lgrs expression in tooth development.
abstract: BACKGROUND
  Tooth development is highly regulated in mammals and it is regulated by networks of signaling pathways (e. g. Tnf, Wnt, Shh, Fgf and Bmp) whose activities are controlled by the balance between ligands, activators, inhibitors and receptors. The members of the R-spondin family are known as activators of Wnt signaling, and Lgr4, Lgr5, and Lgr6 have been identified as receptors for R-spondins. The role of R-spondin/Lgr signaling in tooth development, however, remains unclear.
  
  
  RESULTS
  We first carried out comparative in situ hybridization analysis of R-spondins and Lgrs, and identified their dynamic spatio-temporal expression in murine odontogenesis. R-spondin2 expression was found both in tooth germs and the tooth-less region, the diastema. We further examined tooth development in R-spondin2 mutant mice, and although molars and incisors exhibited no significant abnormalities, supernumerary teeth were observed in the diastema.
  
  
  CONCLUSIONS
  R-spondin/Lgr signaling is thus involved in tooth development.
authors.affiliation: Department of Craniofacial Development and Stem Cell Biology, Dental Institute, King's College London, Guy's Hospital, London Bridge, London, United Kingdom; Division of Bio-Prosthodontics, Department of Oral Health Science, Course for Oral Life Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Maiko
authors.initials: M
authors.lastname: Kawasaki
authors.forename: Thantrira
authors.initials: T
authors.lastname: Porntaveetus
authors.forename: Katsushige
authors.initials: K
authors.lastname: Kawasaki
authors.forename: Shelly
authors.initials: S
authors.lastname: Oommen
authors.forename: Yoko
authors.initials: Y
authors.lastname: Otsuka-Tanaka
authors.forename: Mitsue
authors.initials: M
authors.lastname: Hishinuma
authors.forename: Takato
authors.initials: T
authors.lastname: Nomoto
authors.forename: Takeyasu
authors.initials: T
authors.lastname: Maeda
authors.forename: Keiyo
authors.initials: K
authors.lastname: Takubo
authors.forename: Toshio
authors.initials: T
authors.lastname: Suda
authors.forename: Paul T
authors.initials: PT
authors.lastname: Sharpe
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ohazama
mesh_terms: D000818:Animals; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007180:Incisor / Q000166:cytology / Q000196:embryology*; D051379:Mice; D008963:Molar / Q000166:cytology / Q000196:embryology*; D009805:Odontogenesis / Q000502:physiology*; D043562:Receptors, G-Protein-Coupled / Q000096:biosynthesis*; D019699:Thrombospondins / Q000378:metabolism*
chemical_list: C496200:LGR4 protein, mouse; C116884:LGR5 protein, human; C548022:Lgr6 protein, mouse; D043562:Receptors, G-Protein-Coupled; D019699:Thrombospondins
keywords: Lgrs; R-spondins; diastema; tooth development