title: A Genetic Screen for Mutations Affecting Cell Division in the Arabidopsis thaliana Embryo Identifies Seven Loci Required for Cytokinesis.
abstract: Cytokinesis in plants involves the formation of unique cellular structures such as the phragmoplast and the cell plate, both of which are required to divide the cell after nuclear division. In order to isolate genes that are involved in de novo cell wall formation, we performed a large-scale, microscope-based screen for Arabidopsis mutants that severely impair cytokinesis in the embryo. We recovered 35 mutations that form abnormally enlarged cells with multiple, often polyploid nuclei and incomplete cell walls. These mutants represent seven genes, four of which have previously been implicated in phragmoplast or cell plate function. Mutations in two loci show strongly reduced transmission through the haploid gametophytic generation. Molecular cloning of both corresponding genes reveals that one is represented by hypomorphic alleles of the kinesin-5 gene RADIALLY SWOLLEN 7 (homologous to tobacco kinesin-related protein TKRP125), and that the other gene corresponds to the Arabidopsis FUSED ortholog TWO-IN-ONE (originally identified based on its function in pollen development). No mutations that completely abolish the formation of cross walls in diploid cells were found. Our results support the idea that cytokinesis in the diploid and haploid generations involve similar mechanisms.
authors.affiliation: Department of Plant Biology, Carnegie Institution, Stanford, California, 94305, United States of America.|Department of Biological Sciences, Stanford University, Stanford, California, 94305, United States of America.
authors.forename: C Stewart
authors.initials: CS
authors.lastname: Gillmor
authors.affiliation: Department of Plant Biology, Carnegie Institution, Stanford, California, 94305, United States of America.|Department of Biological Sciences, Stanford University, Stanford, California, 94305, United States of America.
authors.forename: Adrienne H K
authors.initials: AH
authors.lastname: Roeder
authors.affiliation: Department of Plant Biology, Carnegie Institution, Stanford, California, 94305, United States of America.
authors.forename: Patrick
authors.initials: P
authors.lastname: Sieber
authors.affiliation: Department of Plant Biology, Carnegie Institution, Stanford, California, 94305, United States of America.|Department of Biological Sciences, Stanford University, Stanford, California, 94305, United States of America.
authors.forename: Chris
authors.initials: C
authors.lastname: Somerville
authors.affiliation: Department of Plant Biology, Carnegie Institution, Stanford, California, 94305, United States of America.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lukowitz
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D048749:Cytokinesis / Q000235:genetics*; D056625:Endosperm / Q000166:cytology / Q000235:genetics; D005787:Gene Frequency; D056426:Genetic Loci; D005819:Genetic Markers; D008938:Mitosis; D008969:Molecular Sequence Data; D010641:Phenotype; D046509:Tissue Culture Techniques
chemical_list: D029681:Arabidopsis Proteins; D005819:Genetic Markers