title: The distribution of Dishevelled in convergently extending mesoderm.
abstract: Convergent extension (CE) is a conserved morphogenetic movement that drives axial lengthening of the primary body axis and depends on the planar cell polarity (PCP) pathway. In Drosophila epithelia, a polarised subcellular accumulation of PCP core components, such as Dishevelled (Dvl) protein, is associated with PCP function. Dvl has long been thought to accumulate in the mediolateral protrusions in Xenopus chordamesoderm cells undergoing CE. Here we present a quantitative analysis of Dvl intracellular localisation in Xenopus chordamesoderm cells. We find that, surprisingly, accumulations previously observed at mediolateral protrusions of chordamesodermal cells are not protrusion-specific but reflect yolk-free cytoplasm and are quantitatively matched by the distribution of the cytoplasm-filling lineage marker dextran. However, separating cell cortex-associated from bulk Dvl signal reveals a statistical enrichment of Dvl in notochord-somite boundary-(NSB)-directed protrusions, which is dependent upon NSB proximity. Dvl puncta were also observed, but only upon elevated overexpression. These puncta showed no statistically significant spatial bias, in contrast to the strongly posteriorly-enriched GFP-Dvl puncta previously reported in zebrafish. We propose that Dvl distribution is more subtle and dynamic than previously appreciated and that in vertebrate mesoderm it reflects processes other than protrusion as such.
authors.affiliation: Department of Craniofacial Development and Stem Cell Biology, Dental Institute, Kings College London, Floor 27 Guy's Tower, Guy's Hospital, Great Maze Pond, London, SE1 9RT, UK.
authors.forename: Eleni
authors.initials: E
authors.lastname: Panousopoulou
authors.forename: Richard A
authors.initials: RA
authors.lastname: Tyson
authors.forename: Till
authors.initials: T
authors.lastname: Bretschneider
authors.forename: Jeremy B A
authors.initials: JB
authors.lastname: Green
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D016764:Cell Polarity; D000072261:Dishevelled Proteins; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D014981:Xenopus / Q000196:embryology / Q000378:metabolism*; D029867:Xenopus Proteins / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C000606586:DVL1 protein, Xenopus; D000072261:Dishevelled Proteins; D029721:Drosophila Proteins; D010750:Phosphoproteins; D029867:Xenopus Proteins; C000606588:dsh protein, Drosophila
keywords: Convergent extension; Dishevelled; Image analysis; Localisation; Planar cell polarity; QuimP; Xenopus