title: The zebrafish down syndrome cell adhesion molecule is involved in cell movement during embryogenesis.
abstract: The Down syndrome cell adhesion molecule (Dscam) is a protein overexpressed in the brains of Down syndrome patients and implicated in mental retardation. Dscam is involved in axon guidance and branching in Drosophila, but cellular roles in vertebrates have yet to be elucidated. To understand its role in vertebrate development, we cloned the zebrafish homolog of Dscam and showed that it shares high amino acid identity and structure with the mammalian homologs. Zebrafish dscam is highly expressed in developing neurons, similar to what has been described in Drosophila and mouse. When dscam expression is diminished by morpholino injection, embryos display few neurons and their axons do not enter stereotyped pathways. Zebrafish dscam is also present at early embryonic stages including blastulation and gastrulation. Its loss results in early morphogenetic defects. dscam knockdown results in impaired cell movement during epiboly as well as in subsequent stages. We propose that migrating cells utilize dscam to remodel the developing embryo.
authors.affiliation: Cellular and Molecular Physiology, Tufts University School of Medicine, 136 Harrison Avenue, M and V 709, Boston, MA 02111, USA.
authors.forename: Dean
authors.initials: D
authors.lastname: Yimlamai
authors.forename: Liza
authors.initials: L
authors.lastname: Konnikova
authors.forename: Larry G
authors.initials: LG
authors.lastname: Moss
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Jay
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019521:Body Patterning; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000502:physiology*; D003001:Cloning, Molecular; D017931:DNA Primers; D004625:Embryo, Nonmammalian / Q000502:physiology; D008969:Molecular Sequence Data; D009024:Morphogenesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015027:Zebrafish / Q000196:embryology; D029961:Zebrafish Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D015815:Cell Adhesion Molecules; D017931:DNA Primers; D029961:Zebrafish Proteins; C499643:dscama protein, zebrafish