title: Tip-1 induces filopodia growth and is important for gastrulation movements during zebrafish development.
abstract: Wnt signaling is essential during animal development and also plays important roles in pathological conditions. Two mayor pathways have been described: the beta-catenin-dependent canonical (or classical) pathway and the beta-catenin-independent non-canonical Wnt pathway. Recent binding studies suggest links between the small PDZ protein TIP-1 (Tax-1 interacting protein) to components of both Wnt pathways. We have cloned and characterized the zebrafish tip-1 gene. Whole mount in situ hybridization and semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) indicated that zebrafish tip-1 is present as a maternal RNA and is ubiquitously expressed during early development. After 24 h of development, tip-1 expression was high in the central nervous system (CNS) whereas only weak expression was detected in the caudal regions of the zebrafish embryo. Tip-1 knockdown using antisense morpholino oligonucleotides, as well as ectopic tip-1 expression, led to elongation defects in zebrafish embryos and larvae. Both knockdown and overexpression of tip-1 resulted in a widened goosecoid (gsc) expression domain in shield stage embryos, led to an abbreviated prechordal plate, and to reduced convergent extension movements during gastrulation. We constructed a green fluorescence protein (GFP)/TIP-1 fusion protein which, when expressed in cultured fibroblasts (ZF4-cells), induced filopodia growth. Our observations indicate a role for TIP-1 in gastrulation movements and in filopodia growth induction.
authors: Department of Moleclar Cellular Biology, University of Leiden, 2333 AL Leiden, The Netherlands.
authors: Jaya
authors: J
authors: Besser
authors: Jelani T D
authors: JT
authors: Leito
authors: David L M
authors: DL
authors: van der Meer
authors: Christoph P
authors: CP
authors: Bagowski
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004625:Embryo, Nonmammalian / Q000737:chemistry / Q000378:metabolism; D005775:Gastrula / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D018398:Homeodomain Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D011554:Pseudopodia / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000235:genetics; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*
chemical_list: D018398:Homeodomain Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D029961:Zebrafish Proteins; C520605:tax1bp3 protein, zebrafish; D049452:Green Fluorescent Proteins