title: Cortical microtubule nucleation can organise the cytoskeleton of Drosophila oocytes to define the anteroposterior axis.
abstract: Many cells contain non-centrosomal arrays of microtubules (MTs), but the assembly, organisation and function of these arrays are poorly understood. We present the first theoretical model for the non-centrosomal MT cytoskeleton in Drosophila oocytes, in which bicoid and oskar mRNAs become localised to establish the anterior-posterior body axis. Constrained by experimental measurements, the model shows that a simple gradient of cortical MT nucleation is sufficient to reproduce the observed MT distribution, cytoplasmic flow patterns and localisation of oskar and naive bicoid mRNAs. Our simulations exclude a major role for cytoplasmic flows in localisation and reveal an organisation of the MT cytoskeleton that is more ordered than previously thought. Furthermore, modulating cortical MT nucleation induces a bifurcation in cytoskeletal organisation that accounts for the phenotypes of polarity mutants. Thus, our three-dimensional model explains many features of the MT network and highlights the importance of differential cortical MT nucleation for axis formation.
authors.affiliation: Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Philipp
authors.initials: P
authors.lastname: Khuc Trong
authors.affiliation: Wellcome Trust/Cancer Research UK Gurdon Institute, Henry Wellcome Building of Cancer and Developmental Biology, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Hélène
authors.initials: H
authors.lastname: Doerflinger
authors.affiliation: Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Jörn
authors.initials: J
authors.lastname: Dunkel
authors.affiliation: Wellcome Trust/Cancer Research UK Gurdon Institute, Henry Wellcome Building of Cancer and Developmental Biology, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Daniel
authors.initials: D
authors.lastname: St Johnston
authors.affiliation: Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Raymond E
authors.initials: RE
authors.lastname: Goldstein
mesh_terms: D000818:Animals; D016764:Cell Polarity; D004330:Drosophila; D029721:Drosophila Proteins / Q000096:biosynthesis; D018398:Homeodomain Proteins / Q000096:biosynthesis; D008870:Microtubules / Q000378:metabolism*; D008962:Models, Theoretical; D009865:Oocytes / Q000502:physiology*; D055503:Protein Multimerization; D012333:RNA, Messenger / Q000096:biosynthesis; D015534:Trans-Activators / Q000096:biosynthesis
chemical_list: D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; C056478:bcd protein, Drosophila; C091675:osk protein, Drosophila
keywords: D. melanogaster; cell biology; cytoplasmic streaming; cytoskeleton; developmental biology; mRNA transport; stem cells