title: The Arabidopsis kinesin gene AtKin-1 plays a role in the nuclear division process during megagametogenesis.
abstract: Atkin - 1 , the only Kinesin-1 member of Arabidopsis thaliana , plays a role during female gametogenesis through regulation of nuclear division cycles. Kinesins are microtubule-dependent motor proteins found in eukaryotic organisms. They constitute a superfamily that can be further classified into at least 14 families. In the Kinesin-1 family, members from animal and fungi play roles in long-distance transport of organelles and vesicles. Although Kinesin-1-like sequences have been identified in higher plants, little is known about their function in plant cells, other than in a recently identified Kinesin-1-like protein in a rice pollen semi-sterile mutant. In this study, the gene encoding the only Kinesin-1 member in Arabidopsis, AtKin-1 was found to be specifically expressed in ovules and anthers. AtKin-1 loss-of-function mutants showed substantially aborted ovules in siliques, and this finding was supported by complementation testing. Reciprocal crossing between mutant and wild-type plants indicated that a defect in AtKin-1 results in partially aborted megagametophytes, with no observable effects on pollen fertility. Further observation of ovule development in the mutant pistils indicated that the enlargement of the megaspore was blocked and nuclear division arrested at the one-nucleate stage during embryo sac formation. Our data suggest that AtKin-1 plays a role in the nuclear division cycles during megagametogenesis.
authors.affiliation: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Plateau Institute of Biology, Chinese Academy of Sciences, 23 Xinning Road, Xining, 810001, China, wanghq@nwipb.cas.cn.
authors.forename: Haiqing
authors.initials: H
authors.lastname: Wang
authors.forename: Ruijuan
authors.initials: R
authors.lastname: Liu
authors.forename: Jianwu
authors.initials: J
authors.lastname: Wang
authors.forename: Pei
authors.initials: P
authors.lastname: Wang
authors.forename: Yuhu
authors.initials: Y
authors.lastname: Shen
authors.forename: Guoqin
authors.initials: G
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D048750:Cell Nucleus Division / Q000235:genetics*; D035264:Flowers / Q000235:genetics; D056130:Gametogenesis, Plant / Q000235:genetics*; D017930:Genes, Reporter; D005838:Genotype; D016547:Kinesins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009928:Organ Specificity; D056771:Ovule / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D011058:Pollen / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D029681:Arabidopsis Proteins; D016547:Kinesins