title: The circadian clock in Arabidopsis roots is a simplified slave version of the clock in shoots.
abstract: The circadian oscillator in eukaryotes consists of several interlocking feedback loops through which the expression of clock genes is controlled. It is generally assumed that all plant cells contain essentially identical and cell-autonomous multiloop clocks. Here, we show that the circadian clock in the roots of mature Arabidopsis plants differs markedly from that in the shoots and that the root clock is synchronized by a photosynthesis-related signal from the shoot. Two of the feedback loops of the plant circadian clock are disengaged in roots, because two key clock components, the transcription factors CCA1 and LHY, are able to inhibit gene expression in shoots but not in roots. Thus, the plant clock is organ-specific but not organ-autonomous.
authors.affiliation: Division of Molecular and Cellular Biology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Allan B
authors.initials: AB
authors.lastname: James
authors.forename: José A
authors.initials: JA
authors.lastname: Monreal
authors.forename: Gillian A
authors.initials: GA
authors.lastname: Nimmo
authors.forename: Ciarán L
authors.initials: CL
authors.lastname: Kelly
authors.forename: Pawel
authors.initials: P
authors.lastname: Herzyk
authors.forename: Gareth I
authors.initials: GI
authors.lastname: Jenkins
authors.forename: Hugh G
authors.initials: HG
authors.lastname: Nimmo
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D001683:Biological Clocks / Q000235:genetics; D002940:Circadian Rhythm / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D003624:Darkness; D004237:Diuron / Q000494:pharmacology; D025461:Feedback, Physiological; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D008027:Light; D020411:Oligonucleotide Array Sequence Analysis; D010788:Photosynthesis; D018517:Plant Roots / Q000235:genetics / Q000502:physiology*; D018520:Plant Shoots / Q000235:genetics / Q000502:physiology; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; C114425:CCA1 protein, Arabidopsis; D004268:DNA-Binding Proteins; C113192:LHY protein, Arabidopsis; C411822:TOC1 protein, Arabidopsis; D014157:Transcription Factors; D004237:Diuron