title: Cellularisation in the endosperm of Arabidopsis thaliana is coupled to mitosis and shares multiple components with cytokinesis.
abstract: Distinct forms of cytokinesis characterise specific phases of development in plants. In Arabidopsis, as in many other species, the endosperm that nurtures the embryo in the seed initially develops as a syncytium. This syncytial phase ends with simultaneous partitioning of the multinucleate cytoplasm into individual cells, a process referred to as cellularisation. Our in vivo observations show that, as in cytokinesis, cellularisation of the Arabidopsis endosperm is coupled to nuclear division. A genetic analysis reveals that most Arabidopsis mutations affecting cytokinesis in the embryo also impair endosperm cellularisation. These results imply that cellularisation and cytokinesis share multiple components of the same basic machinery. We further report the identification of mutations in a novel gene, SPATZLE, that specifically interfere with cellularisation of the endosperm, but not with cytokinesis in the embryo. The analysis of this mutant might identify a specific checkpoint for the onset of cellularisation.
authors.affiliation: Laboratoire de Reproduction et Développement des Plantes, UMR 5667, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, F-69364 Lyon, Cedex 07, France.
authors.forename: Mikael Blom
authors.initials: MB
authors.lastname: Sørensen
authors.forename: Ulrike
authors.initials: U
authors.lastname: Mayer
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lukowitz
authors.forename: Hélène
authors.initials: H
authors.lastname: Robert
authors.forename: Pierre
authors.initials: P
authors.lastname: Chambrier
authors.forename: Gerd
authors.initials: G
authors.lastname: Jürgens
authors.forename: Chris
authors.initials: C
authors.lastname: Somerville
authors.forename: Loic
authors.initials: L
authors.lastname: Lepiniec
authors.forename: Frédéric
authors.initials: F
authors.lastname: Berger
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002455:Cell Division; D002467:Cell Nucleus / Q000502:physiology; D002473:Cell Wall; D002874:Chromosome Mapping; D006720:Homozygote; D018613:Microscopy, Confocal; D008938:Mitosis; D009154:Mutation; D010641:Phenotype; D013997:Time Factors
chemical_list: D029681:Arabidopsis Proteins