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Science 339 (6125): 1316-1319

Copyright © 2013 by the American Association for the Advancement of Science

Circadian Control of Chloroplast Transcription by a Nuclear-Encoded Timing Signal

Zeenat B. Noordally,1 Kenyu Ishii,2 Kelly A. Atkins,3 Sarah J. Wetherill,3 Jelena Kusakina,4 Eleanor J. Walton,3 Maiko Kato,2 Miyuki Azuma,5 Kan Tanaka,6 Mitsumasa Hanaoka,2 Antony N. Dodd4,*

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.

1 SynthSys, University of Edinburgh, C H Waddington Building, Mayfield Road, Edinburgh EH9 3JD, UK.
2 Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo, Chiba 271-8510, Japan.
3 Department of Biology, University of York, York YO10 5DD, UK.
4 School of Biological Sciences, University of Bristol, Bristol BS8 1UG, UK.
5 Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
6 Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.

* To whom correspondence should be addressed. E-mail: antony.dodd{at}

Subfunctionalization of Sigma Factors during the Evolution of Land Plants Based on Mutant Analysis of Liverwort (Marchantia polymorpha L.) MpSIG1.
M. Ueda, T. Takami, L. Peng, K. Ishizaki, T. Kohchi, T. Shikanai, and Y. Nishimura (2013)
Genome Biol Evol 5, 1836-1848
   Abstract »    Full Text »    PDF »
Characterization of Four Nuclear-Encoded Plastid RNA Polymerase Sigma Factor Genes in the Liverwort Marchantia polymorpha: Blue-Light- and Multiple Stress-Responsive SIG5 was Acquired Early in the Emergence of Terrestrial Plants.
T. Kanazawa, K. Ishizaki, T. Kohchi, M. Hanaoka, and K. Tanaka (2013)
Plant Cell Physiol. 54, 1736-1748
   Abstract »    Full Text »    PDF »

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