title: Female gametophytic cell specification and seed development require the function of the putative Arabidopsis INCENP ortholog WYRD.
abstract: In plants, gametes, along with accessory cells, are formed by the haploid gametophytes through a series of mitotic divisions, cell specification and differentiation events. How the cells in the female gametophyte of flowering plants differentiate into gametes (the egg and central cell) and accessory cells remains largely unknown. In a screen for mutations that affect egg cell differentiation in Arabidopsis, we identified the wyrd (wyr) mutant, which produces additional egg cells at the expense of the accessory synergids. WYR not only restricts gametic fate in the egg apparatus, but is also necessary for central cell differentiation. In addition, wyr mutants impair mitotic divisions in the male gametophyte and endosperm, and have a parental effect on embryo cytokinesis, consistent with a function of WYR in cell cycle regulation. WYR is upregulated in gametic cells and encodes a putative plant ortholog of the inner centromere protein (INCENP), which is implicated in the control of chromosome segregation and cytokinesis in yeast and animals. Our data reveal a novel developmental function of the conserved cell cycle-associated INCENP protein in plant reproduction, in particular in the regulation of egg and central cell fate and differentiation.
authors.affiliation: Institute of Plant Biology and Zürich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland.
authors.forename: Olga
authors.initials: O
authors.lastname: Kirioukhova
authors.forename: Amal J
authors.initials: AJ
authors.lastname: Johnston
authors.forename: Daniela
authors.initials: D
authors.lastname: Kleen
authors.forename: Christina
authors.initials: C
authors.lastname: Kägi
authors.forename: Ramamurthy
authors.initials: R
authors.lastname: Baskar
authors.forename: James M
authors.initials: JM
authors.lastname: Moore
authors.forename: Helmut
authors.initials: H
authors.lastname: Bäumlein
authors.forename: Rita
authors.initials: R
authors.lastname: Gross-Hardt
authors.forename: Ueli
authors.initials: U
authors.lastname: Grossniklaus
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D018506:Gene Expression Regulation, Plant; D008938:Mitosis; D008969:Molecular Sequence Data; D009154:Mutation; D056771:Ovule / Q000166:cytology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D010802:Phylogeny; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C561718:WYR protein, Arabidopsis