Abstract
Circadian rhythms are oscillations in biological processes that function as a key adaptation to the daily rhythms of most environments. In the model cyanobacterial circadian clock system, the core oscillator proteins are encoded by the gene cluster kaiABC1. Genes with high expression and functional importance, such as the kai genes, are usually encoded by optimal codons, yet the codon-usage bias of the kaiBC genes is not optimized for translational efficiency. We discovered a relationship between codon usage and a general property of circadian rhythms called conditionality; namely, that endogenous rhythmicity is robustly expressed under some environmental conditions but not others2. Despite the generality of circadian conditionality, however, its molecular basis is unknown for any system. Here we show that in the cyanobacterium Synechococcus elongate, non-optimal codon usage was selected as a post-transcriptional mechanism to switch between circadian and non-circadian regulation of gene expression as an adaptive response to environmental conditions. When the kaiBC sequence was experimentally optimized to enhance expression of the KaiB and KaiC proteins, intrinsic rhythmicity was enhanced at cool temperatures that are experienced by this organism in its natural habitat. However, fitness at those temperatures was highest in cells in which the endogenous rhythms were suppressed at cool temperatures as compared with cells exhibiting high-amplitude rhythmicity. These results indicate natural selection against circadian systems in cyanobacteria that are intrinsically robust at cool temperatures. Modulation of circadian amplitude is therefore crucial to its adaptive significance3. Moreover, these results show the direct effects of codon usage on a complex phenotype and organismal fitness. Our work also challenges the long-standing view of directional selection towards optimal codons4,5,6,7, and provides a key example of natural selection against optimal codons to achieve adaptive responses to environmental changes.
This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
Codon optimality in cancer
Oncogene Open Access 28 September 2021
-
Codon usage bias regulates gene expression and protein conformation in yeast expression system P. pastoris
Microbial Cell Factories Open Access 26 April 2021
-
A code within the genetic code: codon usage regulates co-translational protein folding
Cell Communication and Signaling Open Access 09 September 2020
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout




References
Ishiura, M. et al. Expression of a gene cluster kaiABC as a circadian feedback process in cyanobacteria. Science 281, 1519–1523 (1998)
Njus, D., McMurry, L. & Hastings, J. W. Conditionality of circadian rhythmicity: synergistic action of light and temperature. J. Comp. Physiol. 117, 335–344 (1977)
Woelfle, M. A., Ouyang, Y., Phanvijhitsiri, K. & Johnson, C. H. The adaptive value of circadian clocks: an experimental assessment in cyanobacteria. Curr. Biol. 14, 1481–1486 (2004)
Drummond, D. A. & Wilke, C. O. Mistranslation-induced protein misfolding as a dominant constraint on coding-sequence evolution. Cell 134, 341–352 (2008)
Bulmer, M. The selection-mutation-drift theory of synonymous codon usage. Genetics 129, 897–907 (1991)
Plotkin, J. B. & Kudla, G. Synonymous but not the same: the causes and consequences of codon bias. Nature Rev. Genet. 12, 32–42 (2011)
Shah, P. & Gilchrist, M. A. Explaining complex codon usage patterns with selection for translational efficiency, mutation bias, and genetic drift. Proc. Natl Acad. Sci. USA 108, 10231–10236 (2011)
Eyre-Walker, A. & Bulmer, M. Reduced synonymous substitution rate at the start of enterobacterial genes. Nucleic Acids Res. 21, 4599–4603 (1993)
Akashi, H. Synonymous codon usage in Drosophila melanogaster: natural selection and translational accuracy. Genetics 136, 927–935 (1994)
Shah, P. & Gilchrist, M. A. Effect of correlated tRNA abundances on translation errors and evolution of codon usage bias. PLoS Genet. 6, e1001128 (2010)
Zhou, T., Weems, M. & Wilke, C. O. Translationally optimal codons associate with structurally sensitive sites in proteins. Mol. Biol. Evol. 26, 1571–1580 (2009)
Ikemura, T. Correlation between the abundance of Escherichia coli transfer RNAs and the occurrence of the respective codons in its protein genes: a proposal for a synonymous codon choice that is optimal for the E. coli translational system. J. Mol. Biol. 151, 389–409 (1981)
Sharp, P. M. & Li, W. H. The codon adaptation index—a measure of directional synonymous codon usage bias, and its potential applications. Nucleic Acids Res. 15, 1281–1295 (1987)
Lynn, D. J., Singer, G. A. & Hickey, D. A. Synonymous codon usage is subject to selection in thermophilic bacteria. Nucleic Acids Res. 30, 4272–4277 (2002)
Paul, S., Bag, S. K., Das, S., Harvill, E. T. & Dutta, C. Molecular signature of hypersaline adaptation: insights from genome and proteome composition of halophilic prokaryotes. Genome Biol. 9, R70 (2008)
Ouyang, Y., Andersson, C. R., Kondo, T., Golden, S. S. & Johnson, C. H. Resonating circadian clocks enhance fitness in cyanobacteria. Proc. Natl Acad. Sci. USA 95, 8660–8664 (1998)
Liu, Y. et al. Circadian orchestration of gene expression in cyanobacteria. Genes Dev. 9, 1469–1478 (1995)
Ito, H. et al. Cyanobacterial daily life with Kai-based circadian and diurnal genome-wide transcriptional control in Synechococcus elongatus. Proc. Natl Acad. Sci. USA 106, 14168–14173 (2009)
Vijayan, V., Zuzow, R. & O’Shea, E. K. Oscillations in supercoiling drive circadian gene expression in cyanobacteria. Proc. Natl Acad. Sci. USA 106, 22564–22568 (2009)
Vijayan, V., Jain, I. H. & O’Shea, E. K. A high resolution map of a cyanobacterial transcriptome. Genome Biol. 12, R47 (2011)
Woelfle, M. A., Xu, Y., Qin, X. & Johnson, C. H. Circadian rhythms of superhelical status of DNA in cyanobacteria. Proc. Natl Acad. Sci. USA 104, 18819–18824 (2007)
Kudla, G., Murray, A. W., Tollervey, D. & Plotkin, J. B. Coding-sequence determinants of gene expression in Escherichia coli. Science 324, 255–258 (2009)
Tuller, T., Waldman, Y. Y., Kupiec, M. & Ruppin, E. Translation efficiency is determined by both codon bias and folding energy. Proc. Natl Acad. Sci. USA 107, 3645–3650 (2010)
Gu, W., Zhou, T. & Wilke, C. O. A universal trend of reduced mRNA stability near translation-initiation site in prokaryotes and eukaryotes. PLOS Comput. Biol. 6, e1000664 (2010)
Zhou, M. et al. Non-optimal codon usage affects expression, structure and function of clock protein FRQ. Naturehttp://dx.doi.org/10.1038/nature11833 (this issue)
Pittendrigh, C. S. On temperature independence in the clock system controlling emergence time in Drosophila. Proc. Natl Acad. Sci. USA 40, 1018–1029 (1954)
Kondo, T. et al. Circadian rhythms in prokaryotes: luciferase as a reporter of circadian gene expression in cyanobacteria. Proc. Natl Acad. Sci. USA 90, 5672–5676 (1993)
Xu, Y., Mori, T. & Johnson, C. H. Cyanobacterial circadian clockwork: roles of KaiA, KaiB and the kaiBC promoter in regulating KaiC. EMBO J. 22, 2117–2126 (2003)
Nakajima, M., Ito, H. & Kondo, T. In vitro regulation of circadian phosphorylation rhythm of cyanobacterial clock protein KaiC by KaiA and KaiB. FEBS Lett. 584, 898–902 (2010)
Konigsberg, W. & Godson, G. N. Evidence for use of rare codons in the dnaG gene and other regulatory genes of Escherichia coli. Proc. Natl Acad. Sci. USA 80, 687–691 (1983)
Liu, Y., Garceau, N. Y., Loros, J. J. & Dunlap, J. C. Thermally regulated translational control of FRQ mediates aspects of temperature responses in the Neurospora circadian clock. Cell 89, 477–486 (1997)
Sharp, P. M. & Li, W. H. An evolutionary perspective on synonymous codon usage in unicellular organisms. J. Mol. Evol. 24, 28–38 (1986)
Schuster, P., Fontana, W., Stadler, P. F. & Hofacker, I. L. From sequences to shapes and back: a case study in RNA secondary structures. Proc. R. Soc. Lond. B 255, 279–284 (1994)
Bustos, S. A. & Golden, S. S. Expression of the psbDII gene in Synechococcus sp. strain PCC 7942 requires sequences downstream of the transcription start site. J. Bacteriol. 173, 7525–7533 (1991)
Xu, Y., Mori, T. & Johnson, C. H. Circadian clock-protein expression in cyanobacteria: rhythms and phase setting. EMBO J. 19, 3349–3357 (2000)
Xu, Y. et al. Intramolecular regulation of phosphorylation status of the circadian clock protein KaiC. PLoS ONE 4, e7509 (2009)
Izumo, M., Johnson, C. H. & Yamazaki, S. Circadian gene expression in mammalian fibroblasts revealed by real-time luminescence reporting: temperature compensation and damping. Proc. Natl Acad. Sci. USA 100, 16089–16094 (2003)
Acknowledgements
We are grateful for the suggestions of M. Woelfle and the technical assistance of D. Zelli and C. Chintanaphol. This research was supported by grants from the National Institute of General Medical Science to C.H.J. (R01 GM067152 and R01 GM088595) and to Y.L. (GM068496 and GM062591), the Welch Foundation (I-1560) to Y.L., and the National Science Foundation (DEB-0844968) and the Searle Scholars Program to A.R. P.S. acknowledges support from a Burroughs Wellcome Fund Career Award and a David & Lucille Packard Foundation Fellowship awarded to Joshua B. Plotkin.
Author information
Authors and Affiliations
Contributions
Y.X. and P.M. collected data; Y.X., P.M. and Y.L. analysed the experimental data; Y.X., P.S. and A.R. analysed the bioinformatic data; Y.L. and C.H.J. designed the original conceptual basis for the study; Y.X. and C.H.J. designed the experimental bases for the study; Y.X., P.S. and C.H.J. wrote the manuscript. All authors discussed the results and commented on the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary Information
This file contains Supplementary Figures 1-7 and Supplementary Tables 1-10. (PDF 1629 kb)
Rights and permissions
About this article
Cite this article
Xu, Y., Ma, P., Shah, P. et al. Non-optimal codon usage is a mechanism to achieve circadian clock conditionality. Nature 495, 116–120 (2013). https://doi.org/10.1038/nature11942
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nature11942
This article is cited by
-
Codon usage bias regulates gene expression and protein conformation in yeast expression system P. pastoris
Microbial Cell Factories (2021)
-
Codon optimality in cancer
Oncogene (2021)
-
The effects of codon bias and optimality on mRNA and protein regulation
Cellular and Molecular Life Sciences (2021)
-
Comprehensive analysis of coding sequence architecture features and gene expression in Arachis duranensis
Physiology and Molecular Biology of Plants (2021)
-
A code within the genetic code: codon usage regulates co-translational protein folding
Cell Communication and Signaling (2020)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.