title: Positioning of nuclei in Arabidopsis root hairs: an actin-regulated process of tip growth.
abstract: In growing Arabidopsis root hairs, the nucleus locates at a fixed distance from the apex, migrates to a random position during growth arrest, and moves from branch to branch in a mutant with branched hairs. Consistently, an artificial increase of the distance between the nucleus and the apex, achieved by entrapment of the nucleus in a laser beam, stops cell growth. Drug studies show that microtubules are not involved in the positioning of the nucleus but that subapical fine F-actin between the nucleus and the hair apex is required to maintain the nuclear position with respect to the growing apex. Injection of an antibody against plant villin, an actin filament-bundling protein, leads to actin filament unbundling and movement of the nucleus closer to the apex. Thus, the bundled actin at the tip side of the nucleus prevents the nucleus from approaching the apex. In addition, we show that the basipetal movement of the nucleus at root hair growth arrest requires protein synthesis and a functional actin cytoskeleton in the root hair tube.
authors.affiliation: Laboratory of Plant Cell Biology, Wageningen University Arboretumlaan, 4 6703 BD Wageningen, The Netherlands.
authors.forename: Tijs
authors.initials: T
authors.lastname: Ketelaar
authors.forename: Cendrine
authors.initials: C
authors.lastname: Faivre-Moskalenko
authors.forename: John J
authors.initials: JJ
authors.lastname: Esseling
authors.forename: Norbert C A
authors.initials: NC
authors.lastname: de Ruijter
authors.forename: Claire S
authors.initials: CS
authors.lastname: Grierson
authors.forename: Marileen
authors.initials: M
authors.lastname: Dogterom
authors.forename: Anne Mie C
authors.initials: AM
authors.lastname: Emons
mesh_terms: D000199:Actins / Q000378:metabolism*; D017360:Arabidopsis / Q000737:chemistry / Q000235:genetics / Q000254:growth & development*; D002467:Cell Nucleus / Q000502:physiology*; D003599:Cytoskeleton / Q000502:physiology; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D009154:Mutation; D018517:Plant Roots / Q000254:growth & development*
chemical_list: D000199:Actins