Self-Organization Controls Expression More than Abundance of Molecular Components of Transcription and Translation in Confined Cell-Free Gene Expression
17 Pages Posted: 2 Oct 2018 Publication Status: Review Complete
More...Abstract
At cell-relevant reactor volumes, cell-free expression suffers from excessive variability (noise) such that protein concentrations may vary by more than an order of magnitude across a population of identically constructed reaction chambers. Consensus opinion holds that variability in expression is due to the stochastic distribution of expression resources (DNA, RNAP, ribosomes, etc.) across the population of reaction chambers. In contrast, here we find that chamber-to-chamber variation in the expression efficiency generates the large variability in protein production. We show that chambers self-organize into expression centers that control expression efficiency. Chambers that organize into many centers, each having relatively few expression resources, exhibit high expression efficiency. Conversely, chambers that organize into few centers where each has an abundance of resources, exhibit low expression efficiency. A surprising finding is that diluting expression resources reduces chamber-to-chamber variation in protein production, which provides the means to tune expression noise. These results demonstrate that in cell-free systems, self-organization exerts more influence over expression than the abundance of the molecular components of transcription and translation. These observations may elucidate how self-organized, membrane-less structures emerge and function in cells.
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