title: Constitutive expression of CIR1 (RVE2) affects several circadian-regulated processes and seed germination in Arabidopsis.
abstract: Circadian clocks are endogenous auto-regulatory mechanisms that allow organisms, from bacteria to humans, to advantageously time a wide range of activities within 24 h environmental cycles. Here we report the identification and characterization of an MYB-related gene, designated Circadian 1 (CIR1), that is involved in circadian regulation in Arabidopsis. Expression of CIR1 is transiently induced by light and oscillates with a circadian rhythm. The rhythmic expression of CIR1 is controlled by the central oscillator. Constitutive expression of CIR1 resulted in a shorter period length for the rhythms of four central oscillator components, and much lower amplitude for the rhythms of central oscillator components CCA1 and LHY. Furthermore, CIR1 over-expression severely affected the circadian rhythms of its own RNA and those of the slave oscillator EPR1 and effector genes Lhcb and CAT3. Plants that constitutively expressed CIR1 displayed delayed flowering, longer hypocotyls and reduced seed germination in the dark. These results suggest that CIR1 is possibly part of a regulatory feedback loop that controls a subset of the circadian outputs and modulates the central oscillator.
authors.affiliation: National Laboratory for Protein Engineering and Plant Genetic Engineering, Peking-Yale Joint Research Center for Plant Molecular Genetics and AgroBiotechnology, College of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Xiangbo
authors.initials: X
authors.lastname: Zhang
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Chen
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Wang
authors.forename: Zhangliang
authors.initials: Z
authors.lastname: Chen
authors.forename: Hongya
authors.initials: H
authors.lastname: Gu
authors.forename: Li-Jia
authors.initials: LJ
authors.lastname: Qu
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001683:Biological Clocks / Q000502:physiology*; D002374:Catalase / Q000378:metabolism; D002940:Circadian Rhythm / Q000235:genetics / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D035264:Flowers / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D018525:Germination / Q000502:physiology*; D018546:Hypocotyl / Q000254:growth & development; D008027:Light; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D017440:Photoperiod; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; C114425:CCA1 protein, Arabidopsis; C524391:CIR1 protein, Arabidopsis; C092776:CONSTANS protein, Arabidopsis; D004268:DNA-Binding Proteins; C480954:EPR1 protein, Arabidopsis; C418905:FT protein, Arabidopsis; C113192:LHY protein, Arabidopsis; D009687:Nuclear Proteins; D014157:Transcription Factors; C490323:CAT3 protein, Arabidopsis; D002374:Catalase