title: CNI1/ATL31, a RING-type ubiquitin ligase that functions in the carbon/nitrogen response for growth phase transition in Arabidopsis seedlings.
abstract: Plants are able to sense and respond to changes in the balance between carbon (C) and nitrogen (N) metabolite availability, known as the C/N response. During the transition to photoautotrophic growth following germination, growth of seedlings is arrested if a high external C/N ratio is detected. To clarify the mechanisms for C/N sensing and signaling during this transition period, we screened a large collection of FOX transgenic plants, overexpressing full-length cDNAs, for individuals able to continue post-germinative growth under severe C/N stress. One line, cni1-D (carbon/nitrogen insensitive 1-dominant), was shown to have a suppressed sensitivity to C/N conditions at both the physiological and molecular level. The CNI1 cDNA encoded a predicted RING-type ubiquitin ligase previously annotated as ATL31. Overexpression of ATL31 was confirmed to be responsible for the cni1-D phenotype, and a knock-out of this gene resulted in hypersensitivity to C/N conditions during post-germinative growth. The ATL31 protein was confirmed to contain ubiquitin ligase activity using an in vitro assay system. Moreover, removal of this ubiquitin ligase activity from the overexpressed protein resulted in the loss of the mutant phenotype. Taken together, these data demonstrated that CNI1/ATL31 activity is required for the plant C/N response during seedling growth transition.
authors.affiliation: Faculty of Advanced Life Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Sato
authors.forename: Shugo
authors.initials: S
authors.lastname: Maekawa
authors.forename: Shigetaka
authors.initials: S
authors.lastname: Yasuda
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Sonoda
authors.forename: Etsuko
authors.initials: E
authors.lastname: Katoh
authors.forename: Takanari
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Miki
authors.initials: M
authors.lastname: Nakazawa
authors.forename: Motoaki
authors.initials: M
authors.lastname: Seki
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shinozaki
authors.forename: Minami
authors.initials: M
authors.lastname: Matsui
authors.forename: Derek B
authors.initials: DB
authors.lastname: Goto
authors.forename: Akira
authors.initials: A
authors.lastname: Ikeda
authors.forename: Junji
authors.initials: J
authors.lastname: Yamaguchi
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D002244:Carbon / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D018525:Germination; D049452:Green Fluorescent Proteins / Q000032:analysis; D009154:Mutation; D009584:Nitrogen / Q000378:metabolism*; D019697:Onions / Q000235:genetics; D030821:Plants, Genetically Modified / Q000254:growth & development / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000032:analysis; D036226:Seedlings / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D044767:Ubiquitin-Protein Ligases / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D054875:Ubiquitination
chemical_list: D029681:Arabidopsis Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D002244:Carbon; C547213:ATL31 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases; D009584:Nitrogen