title: Identification of oscillatory genes in somitogenesis from functional genomic analysis of a human mesenchymal stem cell model.
abstract: During somitogenesis, oscillatory expression of genes in the notch and wnt signaling pathways plays a key role in regulating segmentation. These oscillations in expression levels are elements of a species-specific developmental mechanism. To date, the periodicity and components of the human clock remain unstudied. Here we show that a human mesenchymal stem/stromal cell (MSC) model can be induced to display oscillatory gene expression. We observed that the known cycling gene HES1 oscillated with a 5 h period consistent with available data on the rate of somitogenesis in humans. We also observed cycling of Hes1 expression in mouse C2C12 myoblasts with a period of 2 h, consistent with previous in vitro and embryonic studies. Furthermore, we used microarray and quantitative PCR (Q-PCR) analysis to identify additional genes that display oscillatory expression both in vitro and in mouse embryos. We confirmed oscillatory expression of the notch pathway gene Maml3 and the wnt pathway gene Nkd2 by whole mount in situ hybridization analysis and Q-PCR. Expression patterns of these genes were disrupted in Wnt3a(tm1Amc) mutants but not in Dll3(pu) mutants. Our results demonstrate that human and mouse in vitro models can recapitulate oscillatory expression observed in embryo and that a number of genes in multiple developmental pathways display dynamic expression in vitro.
authors.affiliation: Division of Human Genetics and Orthopaedic Surgery, Children's Hospital of Philadelphia, 3615 Civic Center Blvd., Philadelphia, PA 19104, USA.
authors.forename: Dilusha A
authors.initials: DA
authors.lastname: William
authors.forename: Biagio
authors.initials: B
authors.lastname: Saitta
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Gibson
authors.forename: Jeremy
authors.initials: J
authors.lastname: Traas
authors.forename: Vladimir
authors.initials: V
authors.lastname: Markov
authors.forename: Dorian M
authors.initials: DM
authors.lastname: Gonzalez
authors.forename: William
authors.initials: W
authors.lastname: Sewell
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Anderson
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Pratt
authors.forename: Eric F
authors.initials: EF
authors.lastname: Rappaport
authors.forename: Kenro
authors.initials: K
authors.lastname: Kusumi
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D019521:Body Patterning / Q000502:physiology*; D002478:Cells, Cultured; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D006801:Humans; D017403:In Situ Hybridization; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D015398:Signal Transduction / Q000502:physiology*; D019170:Somites / Q000502:physiology*