title: The ELF4-ELF3-LUX complex links the circadian clock to diurnal control of hypocotyl growth.
abstract: The circadian clock is required for adaptive responses to daily and seasonal changes in environmental conditions. Light and the circadian clock interact to consolidate the phase of hypocotyl cell elongation to peak at dawn under diurnal cycles in Arabidopsis thaliana. Here we identify a protein complex (called the evening complex)--composed of the proteins encoded by EARLY FLOWERING 3 (ELF3), ELF4 and the transcription-factor-encoding gene LUX ARRHYTHMO (LUX; also known as PHYTOCLOCK 1)--that directly regulates plant growth. ELF3 is both necessary and sufficient to form a complex between ELF4 and LUX, and the complex is diurnally regulated, peaking at dusk. ELF3, ELF4 and LUX are required for the proper expression of the growth-promoting transcription factors encoded by PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and PIF5 (also known as PHYTOCHROME INTERACTING FACTOR 3-LIKE 6) under diurnal conditions. LUX targets the complex to the promoters of PIF4 and PIF5 in vivo. Mutations in PIF4 and/or PIF5 are epistatic to the loss of the ELF4-ELF3-LUX complex, suggesting that regulation of PIF4 and PIF5 is a crucial function of the complex. Therefore, the evening complex underlies the molecular basis for circadian gating of hypocotyl growth in the early evening.
authors.affiliation: Section of Cell & Developmental Biology, Division of Biological Sciences, University of California San Diego 9500 Gilman Drive, La Jolla, California 92093-0130, USA.
authors.forename: Dmitri A
authors.initials: DA
authors.lastname: Nusinow
authors.forename: Anne
authors.initials: A
authors.lastname: Helfer
authors.forename: Elizabeth E
authors.initials: EE
authors.lastname: Hamilton
authors.forename: Jasmine J
authors.initials: JJ
authors.lastname: King
authors.forename: Takato
authors.initials: T
authors.lastname: Imaizumi
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Schultz
authors.forename: Eva M
authors.initials: EM
authors.lastname: Farré
authors.forename: Steve A
authors.initials: SA
authors.lastname: Kay
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000254:growth & development / Q000502:physiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D057906:Circadian Clocks / Q000502:physiology* / Q000528:radiation effects; D002940:Circadian Rhythm / Q000502:physiology* / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant; D018546:Hypocotyl / Q000166:cytology / Q000254:growth & development* / Q000528:radiation effects; D008027:Light; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D011485:Protein Binding; D014157:Transcription Factors / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D046912:Multiprotein Complexes; D014157:Transcription Factors; C432430:At2g25930 protein, Arabidopsis; C465973:ELF4 protein, Arabidopsis; C504848:Lux Arrhythmo protein, Arabidopsis; C459466:PIF4 protein, Arabidopsis; C497729:PIF5 protein, Arabidopsis