FIN219, an auxin-regulated gene, defines a link between phytochrome A and the downstream regulator COP1 in light control of Arabidopsis development.
Light signals perceived by photoreceptors are transduced to negatively regulate COP1, a key repressor of photomorphogenic development. To identify genes involved in light inactivation of COP1, a genetic screen was employed to identify extragenic modifier mutations of a temperature-sensitive cop1 allele. One suppressor mutation isolated also exhibited a far-red-specific long hypocotyl phenotype in a wild-type background. Further phenotypic analyses of this new mutation, named fin219, suggested that it defines a novel phytochrome A signaling component. Genetic analysis indicated that FIN219 interacts closely with another phytochrome A signaling component, FHY1. Molecular characterization of FIN219 indicated that it encodes a cytoplasmic localized protein highly similar to the GH3 family of proteins and its expression is rapidly induced by auxin. In contrast to its loss-of-function mutant phenotype, overexpression of FIN219 results in a far-red-specific hyperphotomorphogenic response. Our data suggest that FIN219 may define a critical link for phytochrome A-mediated far-red inactivation of COP1 and a possible cross-talk juncture between auxin regulation and phytochrome signaling.
Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8104 USA.
H L
HL
Hsieh
H
H
Okamoto
M
M
Wang
L H
LH
Ang
M
M
Matsui
H
H
Goodman
X W
XW
Deng
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D029681:Arabidopsis Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D016153:Genes, Suppressor; D005816:Genetic Complementation Test; D018525:Germination; D007210:Indoleacetic Acids / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010834:Phytochrome / Q000378:metabolism*; D051942:Phytochrome A; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D030262:Soybean Proteins; D013395:Sucrose / Q000378:metabolism; D013696:Temperature; D044767:Ubiquitin-Protein Ligases; D010453:Peptide Synthases
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D007210:Indoleacetic Acids; D010834:Phytochrome; D051942:Phytochrome A; D010940:Plant Proteins; D030262:Soybean Proteins; D013395:Sucrose; D044767:Ubiquitin-Protein Ligases; C412831:AT2G46370 protein, Arabidopsis; D010453:Peptide Synthases; C070797:GH3 protein, soybean; C497973:PHYA protein, Arabidopsis; C471983:AT2G32950 protein, Arabidopsis