title: Pleiotropic effects of zebrafish protein-tyrosine phosphatase-1B on early embryonic development.
abstract: Protein tyrosine phosphorylation is an important mechanism of eukaryotic cell signalling which is regulated by protein-tyrosine kinases and protein-tyrosine phosphatases. Here we report the molecular cloning of the first zebrafish protein-tyrosine phosphatase, zf-PTP-1B, the homologue of human PTP-1B. Zf-PTP-1B was catalytically active and localised to the endoplasmic reticulum, like human PTP-1B. Zf-PTP-1B was maternally expressed in zebrafish embryos, and low ubiquitous expression was detected up to day 7 of development. Microinjection of zf-PTP-1B RNA induced pleiotropic, but reproducible developmental defects. Evaluation of the live embryos at 24 h post fertilisation indicated that zf-PTP-1B induced defects in somite formation. The phenotype was dependent on protein-tyrosine phosphatase activity of zf-PTP-1B, since embryos injected with catalytically inactive zf-PTP-1B-C213S developed normally. Co-injection of wild type and inactive zf-PTP-1B led to a rescue of the zf-PTP-1B-induced phenotype, suggesting that zf-PTP-1B-C213S had dominant negative activity. The zf-PTP-1B-induced phenotype suggests that proper tyrosine phosphorylation of key proteins is essential for early development, most notably somitogenesis.
authors.affiliation: Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Utrecht.
authors.forename: A M
authors.initials: AM
authors.lastname: van der Sar
authors.forename: J
authors.initials: J
authors.lastname: de Fockert
authors.forename: M
authors.initials: M
authors.lastname: Betist
authors.forename: D
authors.initials: D
authors.lastname: Zivković
authors.forename: J
authors.initials: J
authors.lastname: den Hertog
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000201:enzymology; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010641:Phenotype; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D017027:Protein Tyrosine Phosphatases