title: FKF1 and GIGANTEA complex formation is required for day-length measurement in Arabidopsis.
abstract: Precise timing of CONSTANS (CO) gene expression is necessary for day-length discrimination for photoperiodic flowering. The FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (FKF1), and GIGANTEA (GI) proteins regulate CO transcription in Arabidopsis. We demonstrate that FKF1 and GI proteins form a complex in a blue-light-dependent manner. The timing of this interaction regulates the timing of daytime CO expression. FKF1 function is dependent on GI, which interacts with a CO repressor, CYCLING DOF FACTOR 1 (CDF1), and controls CDF1 stability. GI, FKF1, and CDF1 proteins associate with CO chromatin. Thus, the FKF1-GI complex forms on the CO promoter in late afternoon to regulate CO expression, providing a mechanistic view of how the coincidence of light with circadian timing regulates photoperiodic flowering.
authors.affiliation: Department of Biochemistry, Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
authors.forename: Mariko
authors.initials: M
authors.lastname: Sawa
authors.forename: Dmitri A
authors.initials: DA
authors.lastname: Nusinow
authors.forename: Steve A
authors.initials: SA
authors.lastname: Kay
authors.forename: Takato
authors.initials: T
authors.lastname: Imaizumi
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D002940:Circadian Rhythm; D004268:DNA-Binding Proteins / Q000235:genetics*; D035264:Flowers / Q000235:genetics / Q000254:growth & development*; D018506:Gene Expression Regulation, Plant; D008027:Light; D009154:Mutation; D017440:Photoperiod; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; C502170:CDF1 protein, Arabidopsis; C092776:CONSTANS protein, Arabidopsis; D002843:Chromatin; D004268:DNA-Binding Proteins; C410504:FKF1 protein, Arabidopsis; C121183:GI protein, Arabidopsis; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors