title: The E3 Ubiquitin Ligase COP1 Regulates Thermosensory Flowering by Triggering GI Degradation in Arabidopsis.
abstract: Floral transition is influenced by environmental factors such as light and temperature. Plants are capable of integrating photoperiod and ambient temperature signaling into their developmental program. Despite extensive investigations on individual genetic pathways, little is known about the molecular components that integrate both pathways. Here, we demonstrate that the RING finger-containing E3 ubiquitin ligase CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) acts as an integrator of photoperiod and ambient temperature signaling. In addition to the role in photoperiodic destabilization of CONSTANS (CO), COP1 also regulates temperature sensitivity by controlling the degradation of GIGANTEA (GI). COP1-impaired mutants showed reduced sensitivity to low ambient temperature. Notably, COP1 is more stabilized at low temperature and accelerates GI turnover in a 26S proteasome-dependent manner. The direct association of GI with the promoter of FLOWERING LOCUS T (FT) was reduced because of its ambient temperature-dependent protein stability control, and thus COP1-triggered GI turnover delays flowering at low temperatures via a CO-independent pathway. Taken together, our findings indicate that environmental conditions regulate the stability of COP1, and conditional specificity of its target selection stimulates proper developmental responses and ensures reproductive success.
authors.affiliation: Department of Bioactive Material Sciences and Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Kiyoung
authors.initials: K
authors.lastname: Jang
authors.affiliation: Department of Bioactive Material Sciences and Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Hong Gil
authors.initials: HG
authors.lastname: Lee
authors.affiliation: Department of Chemistry and Research Institute of Physics and Chemistry, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Su-Jin
authors.initials: SJ
authors.lastname: Jung
authors.affiliation: Department of Plant Science, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Nam-Chon
authors.initials: NC
authors.lastname: Paek
authors.affiliation: 1] Department of Bioactive Material Sciences and Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756, Republic of Korea [2] Department of Chemistry and Research Institute of Physics and Chemistry, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Pil Joon
authors.initials: PJ
authors.lastname: Seo
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D003080:Cold Temperature; D004268:DNA-Binding Proteins / Q000235:genetics; D035264:Flowers / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D008027:Light; D009687:Nuclear Proteins / Q000235:genetics; D017440:Photoperiod; D011401:Promoter Regions, Genetic / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D044767:Ubiquitin-Protein Ligases / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases