title: Inhibition of embryonic development by microcystin-LR in zebrafish, Danio rerio.
abstract: Microcystin-LR (MC-LR), a cyanobacterial toxin, is a potent inhibitor of protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A). PP1 and PP2A are critical regulators in embryonic development. However, the effects of MC-LR in embryonic development have been controversial. MC-LR has been demonstrated to be highly toxic in medaka, but not in zebrafish or rabbit embryos. The causes of difference may be due to membrane impermeability that impaired the delivery of MC-LR into cytoplasm of zebrafish and rabbit embryos. Therefore, we microinjected MC-LR directly into developing zebrafish embryos and investigated the effects of MC-LR on embryonic development. We demonstrated that MC-LR induced the lethality of zebrafish embryos in a dose- and time-dependent manner. MC-LR also induced the loss of blastomere coherence via the interference of beta-catenin and cadherins distributions. Furthermore, the MC-LR treated fry revealed various developmental defects. These results suggested that MC-LR might affect the phosphorylation equilibrium of signaling molecules, including beta-catenin and cadherins, required early in zebrafish embryonic development.
authors.affiliation: Institute of Fisheries Science, National Taiwan University, Taipei, Taiwan, ROC.
authors.forename: Pei-Jen
authors.initials: PJ
authors.lastname: Wang
authors.forename: Ming-Shan
authors.initials: MS
authors.lastname: Chien
authors.forename: Fong-June
authors.initials: FJ
authors.lastname: Wu
authors.forename: Hong-Nong
authors.initials: HN
authors.lastname: Chou
authors.forename: Shyh-Jye
authors.initials: SJ
authors.lastname: Lee
mesh_terms: D000818:Animals; D001757:Blastomeres / Q000187:drug effects; D015820:Cadherins / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004625:Embryo, Nonmammalian / Q000187:drug effects* / Q000378:metabolism; D047108:Embryonic Development / Q000187:drug effects; D008387:Marine Toxins / Q000633:toxicity*; D052998:Microcystins; D010456:Peptides, Cyclic / Q000633:toxicity*; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology; D029961:Zebrafish Proteins; D051176:beta Catenin
chemical_list: D015820:Cadherins; D003598:Cytoskeletal Proteins; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D015534:Trans-Activators; D029961:Zebrafish Proteins; D051176:beta Catenin; C495269:ctnnb1 protein, zebrafish; C057862:cyanoginosin LR