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The effect of natural selection on the propagation of protein expression noise to bacterial growth
In bacterial cells, protein expression is a highly stochastic process. Gene expression noise moreover propagates through the cell and adds to fluctuations in the cellular growth rate. A common intuition is that, due to their relatively high noise amplitudes, proteins with a low mean expression level...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8321134/ https://www.ncbi.nlm.nih.gov/pubmed/34280182 http://dx.doi.org/10.1371/journal.pcbi.1009208 |
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author | Krah, Laurens H. J. Hermsen, Rutger |
author_facet | Krah, Laurens H. J. Hermsen, Rutger |
author_sort | Krah, Laurens H. J. |
collection | PubMed |
description | In bacterial cells, protein expression is a highly stochastic process. Gene expression noise moreover propagates through the cell and adds to fluctuations in the cellular growth rate. A common intuition is that, due to their relatively high noise amplitudes, proteins with a low mean expression level are the most important drivers of fluctuations in physiological variables. In this work, we challenge this intuition by considering the effect of natural selection on noise propagation. Mathematically, the contribution of each protein species to the noise in the growth rate depends on two factors: the noise amplitude of the protein’s expression level, and the sensitivity of the growth rate to fluctuations in that protein’s concentration. We argue that natural selection, while shaping mean abundances to increase the mean growth rate, also affects cellular sensitivities. In the limit in which cells grow optimally fast, the growth rate becomes most sensitive to fluctuations in highly abundant proteins. This causes abundant proteins to overall contribute strongly to the noise in the growth rate, despite their low noise levels. We further explore this result in an experimental data set of protein abundances, and test key assumptions in an evolving, stochastic toy model of cellular growth. |
format | Online Article Text |
id | pubmed-8321134 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-83211342021-07-31 The effect of natural selection on the propagation of protein expression noise to bacterial growth Krah, Laurens H. J. Hermsen, Rutger PLoS Comput Biol Research Article In bacterial cells, protein expression is a highly stochastic process. Gene expression noise moreover propagates through the cell and adds to fluctuations in the cellular growth rate. A common intuition is that, due to their relatively high noise amplitudes, proteins with a low mean expression level are the most important drivers of fluctuations in physiological variables. In this work, we challenge this intuition by considering the effect of natural selection on noise propagation. Mathematically, the contribution of each protein species to the noise in the growth rate depends on two factors: the noise amplitude of the protein’s expression level, and the sensitivity of the growth rate to fluctuations in that protein’s concentration. We argue that natural selection, while shaping mean abundances to increase the mean growth rate, also affects cellular sensitivities. In the limit in which cells grow optimally fast, the growth rate becomes most sensitive to fluctuations in highly abundant proteins. This causes abundant proteins to overall contribute strongly to the noise in the growth rate, despite their low noise levels. We further explore this result in an experimental data set of protein abundances, and test key assumptions in an evolving, stochastic toy model of cellular growth. Public Library of Science 2021-07-19 /pmc/articles/PMC8321134/ /pubmed/34280182 http://dx.doi.org/10.1371/journal.pcbi.1009208 Text en © 2021 Krah, Hermsen https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Krah, Laurens H. J. Hermsen, Rutger The effect of natural selection on the propagation of protein expression noise to bacterial growth |
title | The effect of natural selection on the propagation of protein expression noise to bacterial growth |
title_full | The effect of natural selection on the propagation of protein expression noise to bacterial growth |
title_fullStr | The effect of natural selection on the propagation of protein expression noise to bacterial growth |
title_full_unstemmed | The effect of natural selection on the propagation of protein expression noise to bacterial growth |
title_short | The effect of natural selection on the propagation of protein expression noise to bacterial growth |
title_sort | effect of natural selection on the propagation of protein expression noise to bacterial growth |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8321134/ https://www.ncbi.nlm.nih.gov/pubmed/34280182 http://dx.doi.org/10.1371/journal.pcbi.1009208 |
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