51. Tip-1 induces filopodia growth and is important for gastrulation movements during zebrafish development
- Author
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Jaya, Besser, Jelani T D, Leito, David L M, van der Meer, and Christoph P, Bagowski
- Subjects
Homeodomain Proteins ,Embryo, Nonmammalian ,Recombinant Fusion Proteins ,Green Fluorescent Proteins ,Molecular Sequence Data ,Animals ,Amino Acid Sequence ,Gastrula ,Pseudopodia ,RNA, Messenger ,Cloning, Molecular ,Zebrafish Proteins ,Zebrafish - 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.
- Published
- 2007