title: Microtubules regulate dynamic organization of vacuoles in Physcomitrella patens.
abstract: Eukaryotic cells have developed several essential membrane components. In flowering plants, appropriate structures and distributions of the major membrane components are predominantly regulated by actin microfilaments. In this study, we have focused on the regulatory mechanism of vacuolar structures in the moss, Physcomitrella patens. The high ability of P. patens to undergo homologous recombination enabled us stably to express green fluorescent protein (GFP) or red fluorescent protein (RFP) fusion proteins, and the simple body structure of P. patens enabled us to perform detailed visualization of the intracellular vacuolar and cytoskeletal structures. Three-dimensional analysis and high-speed time-lapse observations revealed surprisingly complex structures and dynamics of the vacuole, with inner sheets and tubular protrusions, and frequent rearrangements by separation and fusion of the membranes. Depolymerization of microtubules dramatically affected these structures and movements. Dual observation of microtubules and vacuolar membranes revealed that microtubules induced tubular protrusions and cytoplasmic strands of the vacuoles, indicative of interactions between microtubules and vacuolar membranes. These results demonstrate a novel function of microtubules in maintaining the distribution of the vacuole and suggest a functional divergence of cytoskeletal functions in land plant evolution.
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8562, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Oda
authors.forename: Aiko
authors.initials: A
authors.lastname: Hirata
authors.forename: Toshio
authors.initials: T
authors.lastname: Sano
authors.forename: Tomomichi
authors.initials: T
authors.lastname: Fujita
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hiwatashi
authors.forename: Yoshikatsu
authors.initials: Y
authors.lastname: Sato
authors.forename: Akeo
authors.initials: A
authors.lastname: Kadota
authors.forename: Mitsuyasu
authors.initials: M
authors.lastname: Hasebe
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Hasezawa
mesh_terms: D019068:Bryopsida / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D021621:Imaging, Three-Dimensional; D007425:Intracellular Membranes / Q000648:ultrastructure*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008870:Microtubules / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism / Q000648:ultrastructure*; D000097573:Red Fluorescent Protein
chemical_list: D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D000097573:Red Fluorescent Protein