title: Circadian control of chloroplast transcription by a nuclear-encoded timing signal.
abstract: Circadian timekeeping in plants increases photosynthesis and productivity. There are circadian oscillations in the abundance of many chloroplast-encoded transcripts, but it is not known how the circadian clock regulates chloroplast transcription or the photosynthetic apparatus. We show that, in Arabidopsis, nuclear-encoded SIGMA FACTOR5 (SIG5) controls circadian rhythms of transcription of several chloroplast genes, revealing one pathway by which the nuclear-encoded circadian oscillator controls rhythms of chloroplast gene expression. We also show that SIG5 mediates the circadian gating of light input to a chloroplast-encoded gene. We have identified an evolutionarily conserved mechanism that communicates circadian timing information between organelles with distinct genetic systems and have established a new level of integration between eukaryotic circadian clocks and organelles of endosymbiotic origin.
authors.affiliation: SynthSys, University of Edinburgh, Edinburgh, UK.
authors.forename: Zeenat B
authors.initials: ZB
authors.lastname: Noordally
authors.forename: Kenyu
authors.initials: K
authors.lastname: Ishii
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Atkins
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Wetherill
authors.forename: Jelena
authors.initials: J
authors.lastname: Kusakina
authors.forename: Eleanor J
authors.initials: EJ
authors.lastname: Walton
authors.forename: Maiko
authors.initials: M
authors.lastname: Kato
authors.forename: Miyuki
authors.initials: M
authors.lastname: Azuma
authors.forename: Kan
authors.initials: K
authors.lastname: Tanaka
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Hanaoka
authors.forename: Antony N
authors.initials: AN
authors.lastname: Dodd
mesh_terms: D021581:Active Transport, Cell Nucleus; D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics*; D002940:Circadian Rhythm; D018506:Gene Expression Regulation, Plant; D045332:Photosystem II Protein Complex / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; D045332:Photosystem II Protein Complex; C479885:PsbD protein, Arabidopsis; C486979:Sig5 protein, Arabidopsis; D012808:Sigma Factor