title: Distinct roles of microRNAs in epithelium and mesenchyme during tooth development.
abstract: BACKGROUND
  Tooth development is known to be mediated by the cross-talk between signaling pathways, including Shh, Fgf, Bmp, and Wnt. MicroRNAs (miRNAs) are 19- to 25-nt noncoding small single-stranded RNAs that negatively regulate gene expression by binding target mRNAs, which is believed to be important for the fine-tuning signaling pathways in development. To investigate the role of miRNAs in tooth development, we examined mice with either mesenchymal (Wnt1Cre/Dicer(fl/fl)) or epithelial (ShhCre/Dicer(fl/fl)) conditional deletion of Dicer, which is essential for miRNA processing.
  
  
  RESULTS
  By using a CD1 genetic background for Wnt1Cre/Dicer(fl/fl), we were able to examine tooth development, because the mutants retained mandible and maxilla primordia. Wnt1Cre/Dicer(fl/fl) mice showed an arrest or absence of teeth development, which varied in frequency between incisors and molars. Extra incisor tooth formation was found in ShhCre/Dicer(fl/fl) mice, whereas molars showed no significant anomalies. Microarray and in situ hybridization analysis identified several miRNAs that showed differential expression between incisors and molars.
  
  
  CONCLUSIONS
  In tooth development, miRNAs thus play different roles in epithelium and mesenchyme, and in incisors and molars.
authors: Craniofacial Development and Stem cell biology, and Biomedical Research Centre, Dental Institute, King's College London, Guy's Hospital, London Bridge, London, UK.
authors: Shelly
authors: S
authors: Oommen
authors: Yoko
authors: Y
authors: Otsuka-Tanaka
authors: Najam
authors: N
authors: Imam
authors: Maiko
authors: M
authors: Kawasaki
authors: Katsushige
authors: K
authors: Kawasaki
authors: Farnoosh
authors: F
authors: Jalani-Ghazani
authors: Angela
authors: A
authors: Anderegg
authors: Rajeshwar
authors: R
authors: Awatramani
authors: Robert
authors: R
authors: Hindges
authors: Paul T
authors: PT
authors: Sharpe
authors: Atsushi
authors: A
authors: Ohazama
mesh_terms: D000818:Animals; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism; D004622:Embryo, Mammalian; D004848:Epithelium / Q000196:embryology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D053823:Hedgehog Proteins / Q000235:genetics / Q000378:metabolism; D019426:Integrases / Q000235:genetics / Q000378:metabolism; D008648:Mesoderm / Q000196:embryology* / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D046228:Microarray Analysis; D009805:Odontogenesis / Q000235:genetics*; D043244:Ribonuclease III / Q000235:genetics / Q000378:metabolism; D014070:Tooth / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D059467:Transcriptome; D051155:Wnt1 Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D053823:Hedgehog Proteins; D035683:MicroRNAs; C465570:Shh protein, mouse; D051155:Wnt1 Protein; C495246:Wnt1 protein, mouse; C045073:Cre recombinase; D019426:Integrases; C509781:Dicer1 protein, mouse; D043244:Ribonuclease III; D053487:DEAD-box RNA Helicases