Cell Reports
Volume 19, Issue 3, 18 April 2017, Pages 497-504
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Cyanobacteria Maintain Constant Protein Concentration despite Genome Copy-Number Variation

https://doi.org/10.1016/j.celrep.2017.03.067Get rights and content
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Highlights

  • S. elongatus protein concentration is constant despite genome copy-number variance

  • Cell volume is positively, linearly correlated with genome copy number

  • Total protein amount is positively, linearly correlated with genome copy number

  • Cell volume changes serve as an important compensation mechanism

Summary

The cyanobacterium Synechococcus elongatus PCC 7942 has multiple copies of its single chromosome, and the copy number varies in individual cells, providing an ideal system to study the effect of genome copy-number variation on cell size and gene expression. Using single-cell fluorescence imaging, we found that protein concentration remained constant across individual cells regardless of genome copy number. Cell volume and the total protein amount from a single gene were both positively, linearly correlated with genome copy number, suggesting that changes in cell volume play an important role in buffering genome copy-number variance. This study provides a quantitative examination of gene expression regulation in cells with variable genome copies and sheds light on the compensation mechanisms for variance in genome copy number.

Keywords

Synechococcus elongatus PCC 7942
compensation
gene expression
genome copy number
cell volume
cell size
protein concentration

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Present address: Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA

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