title: Growing microtubules push the oocyte nucleus to polarize the Drosophila dorsal-ventral axis.
abstract: The Drosophila dorsal-ventral (DV) axis is polarized when the oocyte nucleus migrates from the posterior to the anterior margin of the oocyte. Prior work suggested that dynein pulls the nucleus to the anterior side along a polarized microtubule cytoskeleton, but this mechanism has not been tested. By imaging live oocytes, we find that the nucleus migrates with a posterior indentation that correlates with its direction of movement. Furthermore, both nuclear movement and the indentation depend on microtubule polymerization from centrosomes behind the nucleus. Thus, the nucleus is not pulled to the anterior but is pushed by the force exerted by growing microtubules. Nuclear migration and DV axis formation therefore depend on centrosome positioning early in oogenesis and are independent of anterior-posterior axis formation.
authors.affiliation: The Gurdon Institute and the Department of Genetics, University of Cambridge, Cambridge, UK.
authors.forename: Tongtong
authors.initials: T
authors.lastname: Zhao
authors.forename: Owen S
authors.initials: OS
authors.lastname: Graham
authors.forename: Alexandre
authors.initials: A
authors.lastname: Raposo
authors.forename: Daniel
authors.initials: D
authors.lastname: St Johnston
mesh_terms: D000818:Animals; D019521:Body Patterning; D002467:Cell Nucleus / Q000502:physiology* / Q000648:ultrastructure; D016764:Cell Polarity; D018385:Centrosome / Q000502:physiology; D004330:Drosophila; D029721:Drosophila Proteins / Q000502:physiology; D004398:Dyneins / Q000502:physiology; D022101:Microtubule-Organizing Center / Q000502:physiology / Q000648:ultrastructure; D008870:Microtubules / Q000502:physiology* / Q000648:ultrastructure; D009068:Movement; D009154:Mutation; D009685:Nuclear Envelope / Q000502:physiology / Q000648:ultrastructure; D009865:Oocytes / Q000502:physiology* / Q000648:ultrastructure; D009866:Oogenesis
chemical_list: D029721:Drosophila Proteins; D004398:Dyneins