title: Application of lentivirus-mediated RNAi in studying gene function in mammalian tooth development.
abstract: RNA interference (RNAi) has recently become a powerful tool to silence gene expression in mammalian cells, but its application in assessing gene function in mammalian developing organs remains highly limited. Here we describe several unique developmental properties of the mouse molar germ. Embryonic molar mesenchyme, but not the incisor mesenchyme, once dissociated into single cell suspension and re-aggregated, retains its odontogenic potential, the capability of a tissue to instruct an adjacent tissue to initiate tooth formation. Dissociated molar mesenchymal cells, even after being plated in cell culture, retain odontogenic competence, the capability of a tissue to respond to odontogenic signals and to support tooth formation. Most interestingly, while dissociated epithelial and mesenchymal cells of molar tooth germ are mixed and re-aggregated, the epithelial cells are able to sort out from the mesenchymal cells and organize into a well-defined dental epithelial structure, leading to the formation of a well-differentiated tooth organ after sub-renal culture. These unique molar developmental properties allow us to develop a strategy using a lentivirus-mediated RNAi approach to silence gene expression in dental mesenchymal cells and assess gene function in tooth development. We show that knockdown of Msx1 or Dlx2 expression in the dental mesenchyme faithfully recapitulates the tooth phenotype of their targeted mutant mice. Silencing of Barx1 expression in the dental mesenchyme causes an arrest of tooth development at the bud stage, demonstrating a crucial role for Barx1 in tooth formation. Our studies have established a reliable and rapid assay that would permit large-scale analysis of gene function in mammalian tooth development.
authors.affiliation: Division of Developmental Biology, Department of Cell and Molecular Biology, Tulane University, New Orleans, Louisiana 70118, USA.
authors.forename: Yiqiang
authors.initials: Y
authors.lastname: Song
authors.forename: Zunyi
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xueyan
authors.initials: X
authors.lastname: Yu
authors.forename: Minquan
authors.initials: M
authors.lastname: Yan
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Zhang
authors.forename: Shuping
authors.initials: S
authors.lastname: Gu
authors.forename: Thomas
authors.initials: T
authors.lastname: Stuart
authors.forename: Chao
authors.initials: C
authors.lastname: Liu
authors.forename: Jakob
authors.initials: J
authors.lastname: Reiser
authors.forename: Yanding
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yiping
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000818:Animals; D002460:Cell Line; D018507:Gene Expression Regulation, Developmental; D020868:Gene Silencing; D005822:Genetic Vectors; D006801:Humans; D016086:Lentivirus / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D014070:Tooth / Q000196:embryology* / Q000378:metabolism / Q000821:virology
chemical_list: D034741:RNA, Small Interfering