title: LHY and CCA1 are partially redundant genes required to maintain circadian rhythms in Arabidopsis.
abstract: Several genes are known to regulate circadian rhythms in Arabidopsis, but the identity of the central oscillator has not been established. LHY and CCA1 are related MYB-like transcription factors proposed to be closely involved. Here we demonstrate that, as shown previously for CCA1, inactivation of LHY shortens the period of circadian rhythms in gene expression and leaf movements. By constructing lhy cca1-1 double mutants, we show that LHY and CCA1 are partially redundant and essential for the maintenance of circadian rhythms in constant light. Under light/dark cycles the lhy cca1-1 plants show dramatically earlier phases of expression of GI and TOC1, genes associated with the generation of circadian rhythms and the promotion of LHY and CCA1 expression. We conclude that LHY and CCA1 appear to be negative regulatory elements required for central oscillator function.
authors.affiliation: John Innes Centre, Colney Lane, Norwich NR4 7UH, United Kingdom.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Mizoguchi
authors.forename: Kay
authors.initials: K
authors.lastname: Wheatley
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Hanzawa
authors.forename: Louisa
authors.initials: L
authors.lastname: Wright
authors.forename: Mutsuko
authors.initials: M
authors.lastname: Mizoguchi
authors.forename: Hae Ryong
authors.initials: HR
authors.lastname: Song
authors.forename: Isabelle A
authors.initials: IA
authors.lastname: Carré
authors.forename: George
authors.initials: G
authors.lastname: Coupland
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics*; D002940:Circadian Rhythm / Q000235:genetics* / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018546:Hypocotyl / Q000254:growth & development; D008954:Models, Biological; D009068:Movement; D009154:Mutation; D010641:Phenotype; D017440:Photoperiod; D018515:Plant Leaves / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; C114425:CCA1 protein, Arabidopsis; D004268:DNA-Binding Proteins; C113192:LHY protein, Arabidopsis; D012333:RNA, Messenger; D018749:RNA, Plant; D014157:Transcription Factors