title: Possible functional involvement of thymosin beta 4 in developing tooth germ of mouse lower first molar.
abstract: We examined the detailed in situ expression pattern of thymosin beta 4 (Tbeta4) in the developing mouse mandibular first molar. Tbeta4 mRNA was expressed in the presumptive dental epithelium at embryonic day 10.5 (E10.5) and in the thickened dental epithelium at E12. An in situ signal was observed in the invaginated epithelial bud at E13, in the enamel organ at E14 and E14.5, and in the primary enamel knot (PEK) at E14.5. The signal was localized in the epithelial cells of the outer layer of the enamel organ at E15 and E15.5. No signal was found in the PEK at these stages. Tbeta4 mRNA was expressed in the inner enamel epithelium, cervical loop and dental lamina at E16 and E17. The expression of Tbeta4 mRNA was observed in the polarized inner epithelial cells at E18, newborn day 1 (N1) and N2. However, the signal intensity decreased markedly at N3. We herein report for the first time that Tbeta4 is distinctly expressed in developing tooth germ, and it may also play functional roles in the initiation, growth and differentiation of tooth germ.
authors.affiliation: Laboratory of Oral Pathology and Medicine, Kyushu University Graduate School of Dental Science, 3-1-1 Maidashi, Fukuoka, 812-8582, Japan.
authors.forename: Merina
authors.initials: M
authors.lastname: Akhter
authors.forename: Ieyoshi
authors.initials: I
authors.lastname: Kobayashi
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Kiyoshima
authors.forename: Kou
authors.initials: K
authors.lastname: Matsuo
authors.forename: Haruyoshi
authors.initials: H
authors.lastname: Yamaza
authors.forename: Hiroko
authors.initials: H
authors.lastname: Wada
authors.forename: Jun-ya
authors.initials: JY
authors.lastname: Honda
authors.forename: Xie
authors.initials: X
authors.lastname: Ming
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Sakai
mesh_terms: D000818:Animals; D003743:Dental Enamel / Q000196:embryology / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D017403:In Situ Hybridization; D051379:Mice; D008807:Mice, Inbred BALB C; D008963:Molar / Q000196:embryology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013947:Thymosin / Q000378:metabolism*; D014083:Tooth Germ / Q000196:embryology / Q000378:metabolism*; D000099201:Thymosin beta(4)
chemical_list: D012333:RNA, Messenger; D013947:Thymosin; D000099201:Thymosin beta(4)