title: Light-dependent polyploidy control by a CUE protein variant in Arabidopsis.
abstract: Endoreduplication is a special cell cycle that increases ploidy without cell and nuclear division. In plants endoreduplication is essential for development. We isolated a dominant Arabidopsis mutant from activation tagging lines that had increased polyploidy in darkness. This mutant, ipd1-1D (increased polyploidy level in darkness 1-1D), shows longer hypocotyls and increased ploidy levels only in dark-grown seedlings. The corresponding gene encodes a protein that contains a CUE domain variant. IPD1 is specifically expressed in mitotically dividing cells. Furthermore we show that blue and far-red light can suppress the ploidy increase in ipd1-1D and also suppress the reporter expression in IPD1-promoter beta-glucuronidase transgenic plants. These results suggest that IPD1 regulates the endocycle leading to hypocotyl elongation and this function is controlled by blue and far-red light.
authors.affiliation: Graduate School of Humanities and Science Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Tsumoto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshizumi
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kuroda
authors.forename: Mika
authors.initials: M
authors.lastname: Kawashima
authors.forename: Takanari
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Miki
authors.initials: M
authors.lastname: Nakazawa
authors.forename: Naoki
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Minami
authors.initials: M
authors.lastname: Matsui
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D005799:Genes, Dominant / Q000235:genetics; D008027:Light; D008938:Mitosis; D009154:Mutation; D010641:Phenotype; D011123:Polyploidy; D017434:Protein Structure, Tertiary
chemical_list: D029681:Arabidopsis Proteins; C491608:CUE1 protein, Arabidopsis; C514053:IPD1 protein, Arabidopsis