title: Adenovirus-mediated ectopic expression of Msx2 in even-numbered rhombomeres induces apoptotic elimination of cranial neural crest cells in ovo.
abstract: Distinct cranial neural crest-derived cell types (a number of neuronal as well as non-neuronal cell lineages) are generated at characteristic times and positions in the rhombomeres of the hindbrain in developing vertebrate embryos. To examine this developmental process, we developed a novel strategy designed to test the efficacy of gain-of-function Msx2 expression within rhombomeres in ovo prior to the emigration of cranial neural crest cells (CNCC). Previous studies indicate that CNCC from odd-numbered rhombomeres (r3 and r5) undergo apoptosis in response to exogenous BMP4. We provide evidence that targeted infection in ovo using adenovirus containing Msx2 and a reporter molecule indicative of translation can induce apoptosis in either even- or odd-numbered rhombomeres. Furthermore, infected lacZ-control explants indicated that CNCC emigrated, and that 20% of these cells were double positive for crest cell markers HNK-1 and beta-gal. In contrast, there were no HNK-1 and Msx2 double positive cells emigrating from Msx2 infected explants. These results support the hypothesis that apoptotic elimination of CNCC can be induced by 'gain-of-function' Msx2 expression in even-numbered rhombomeres. These inductive interactions involve qualitative, quantitative, positional and temporal differences in TGF-beta-related signals, Msx2 expression and other transcriptional control.
authors.affiliation: Craniofacial Development Section, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892-2745, USA. takahask@irp.niams.nih.gov
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: G H
authors.initials: GH
authors.lastname: Nuckolls
authors.forename: O
authors.initials: O
authors.lastname: Tanaka
authors.forename: I
authors.initials: I
authors.lastname: Semba
authors.forename: I
authors.initials: I
authors.lastname: Takahashi
authors.forename: R
authors.initials: R
authors.lastname: Dashner
authors.forename: L
authors.initials: L
authors.lastname: Shum
authors.forename: H C
authors.initials: HC
authors.lastname: Slavkin
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology; D002465:Cell Movement; D002642:Chick Embryo; D046508:Culture Techniques; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D004848:Epithelium; D015870:Gene Expression; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D018398:Homeodomain Proteins; D006801:Humans; D051379:Mice; D008875:Middle Aged; D009432:Neural Crest / Q000166:cytology / Q000196:embryology*; D012249:Rhombencephalon / Q000166:cytology / Q000196:embryology*; D012886:Skull
chemical_list: C525809:BMP4 protein, human; C525810:Bmp4 protein, mouse; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C084119:MSX2 protein