title: Regulation of proliferation and differentiation of mouse tooth germ epithelial cells by distinct isoforms of p51/p63.
abstract: OBJECTIVE
  p51/p63 gene, one of the p53 families, is specifically expressed in tooth germ epithelial cells and is essential for tooth development. This study aims to elucidate roles of p51/p63 in ameloblastic cell differentiation.
  
  
  METHODS
  We determined expression pattern of each of p51/p63 isoforms by reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting using emtg (epithelium of molar tooth germ)-1, -2, -3, -4, and -5 cell lines established from a mandibular molar tooth germ of p53-deficient mice and SF2 cells which differentiates into ameloblasts upon exposure to NT4. Furthermore, we investigated the function of p51/p63 in these cells by Tet system, which enables inducible expression and knock down of the target genes of interest by exposing cells to doxycycline.
  
  
  RESULTS
  The expression of ΔNp51B/ΔNp63α, an isoform without transactivation domain, was detected at high level in immature cells, while the expression of TAp51/TAp63 isoforms, isoforms of with the transactivation domain, was detected at high level in mature cells. Moreover, induction of TAp51A/TAp63γ expression led to down-regulation of ΔNp51B/ΔNp63α expression and cell proliferation. Interestingly, this also led to up-regulation of ameloblastin expression, a differentiation marker of amelogenesis.
  
  
  CONCLUSIONS
  The results suggested that p51/p63 might regulate the cell proliferation and differentiation of tooth germ epithelial cells.
authors.affiliation: Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryomachi Aoba-ku, Sendai 980-8575, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsuura
authors.forename: Viviane K S
authors.initials: VK
authors.lastname: Kawata
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Nagoshi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tomooka
authors.forename: Keiichi
authors.initials: K
authors.lastname: Sasaki
authors.forename: Shuntaro
authors.initials: S
authors.lastname: Ikawa
mesh_terms: D000256:Adenoviridae; D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation / Q000235:genetics*; D002460:Cell Line; D049109:Cell Proliferation; D002478:Cells, Cultured; D017931:DNA Primers; D003746:Dental Enamel Proteins / Q000378:metabolism; D015536:Down-Regulation; D004318:Doxycycline / Q000494:pharmacology; D004587:Electrophoresis, Agar Gel; D016158:Genes, p53 / Q000502:physiology; D051379:Mice; D010750:Phosphoproteins / Q000502:physiology*; D020033:Protein Isoforms / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014083:Tooth Germ / Q000166:cytology*; D015534:Trans-Activators / Q000502:physiology*; D015533:Transcriptional Activation; D014162:Transfection; D015854:Up-Regulation
chemical_list: C490890:Ambn protein, mouse; D017931:DNA Primers; D003746:Dental Enamel Proteins; D010750:Phosphoproteins; D020033:Protein Isoforms; D015534:Trans-Activators; C486419:Trp63 protein, mouse; D004318:Doxycycline