CNI1/ATL31, a RING-type ubiquitin ligase that functions in the carbon/nitrogen response for growth phase transition in Arabidopsis seedlings.
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.
Sato
Takeo
T
Faculty of Advanced Life Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan.
Maekawa
Shugo
S
Yasuda
Shigetaka
S
Sonoda
Yutaka
Y
Katoh
Etsuko
E
Ichikawa
Takanari
T
Nakazawa
Miki
M
Seki
Motoaki
M
Shinozaki
Kazuo
K
Matsui
Minami
M
Goto
Derek B
DB
Ikeda
Akira
A
Yamaguchi
Junji
J
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
D029681:Arabidopsis Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D002244:Carbon; C547213:ATL31 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases; D009584:Nitrogen