title: Myosin phosphatase Fine-tunes Zebrafish Motoneuron Position during Axonogenesis.
abstract: During embryogenesis the spinal cord shifts position along the anterior-posterior axis relative to adjacent tissues. How motor neurons whose cell bodies are located in the spinal cord while their axons reside in adjacent tissues compensate for such tissue shift is not well understood. Using live cell imaging in zebrafish, we show that as motor axons exit from the spinal cord and extend through extracellular matrix produced by adjacent notochord cells, these cells shift several cell diameters caudally. Despite this pronounced shift, individual motoneuron cell bodies stay aligned with their extending axons. We find that this alignment requires myosin phosphatase activity within motoneurons, and that mutations in the myosin phosphatase subunit mypt1 increase myosin phosphorylation causing a displacement between motoneuron cell bodies and their axons. Thus, we demonstrate that spinal motoneurons fine-tune their position during axonogenesis and we identify the myosin II regulatory network as a key regulator.
authors.affiliation: Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Juliane
authors.identifier: http://orcid.org/0000-0002-0268-9425
authors.initials: J
authors.lastname: Bremer
authors.affiliation: Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Michael
authors.initials: M
authors.lastname: Granato
mesh_terms: D000818:Animals; D001369:Axons; D047108:Embryonic Development / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D009046:Motor Neurons / Q000166:cytology / Q000378:metabolism; D032342:Muscle Cells / Q000166:cytology / Q000378:metabolism; D043263:Myosin-Light-Chain Phosphatase / Q000096:biosynthesis / Q000235:genetics*; D055495:Neurogenesis / Q000235:genetics*; D009672:Notochord / Q000254:growth & development; D013116:Spinal Cord / Q000254:growth & development; D015027:Zebrafish / Q000235:genetics / Q000254:growth & development
chemical_list: D043263:Myosin-Light-Chain Phosphatase