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The Absence of (p)ppGpp Renders Initiation of Escherichia coli Chromosomal DNA Synthesis Independent of Growth Rates

The initiation of Escherichia coli chromosomal DNA replication starts with the oligomerization of the DnaA protein at repeat sequences within the origin (ori) region. The amount of ori DNA per cell directly correlates with the growth rate. During fast growth, the cell generation time is shorter than...

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Autores principales: Fernández-Coll, Llorenç, Maciag-Dorszynska, Monika, Tailor, Krishma, Vadia, Stephen, Levin, Petra Anne, Szalewska-Palasz, Agnieszka, Cashel, Michael
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Microbiology 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7064777/
https://www.ncbi.nlm.nih.gov/pubmed/32156825
http://dx.doi.org/10.1128/mBio.03223-19
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author Fernández-Coll, Llorenç
Maciag-Dorszynska, Monika
Tailor, Krishma
Vadia, Stephen
Levin, Petra Anne
Szalewska-Palasz, Agnieszka
Cashel, Michael
author_facet Fernández-Coll, Llorenç
Maciag-Dorszynska, Monika
Tailor, Krishma
Vadia, Stephen
Levin, Petra Anne
Szalewska-Palasz, Agnieszka
Cashel, Michael
author_sort Fernández-Coll, Llorenç
collection PubMed
description The initiation of Escherichia coli chromosomal DNA replication starts with the oligomerization of the DnaA protein at repeat sequences within the origin (ori) region. The amount of ori DNA per cell directly correlates with the growth rate. During fast growth, the cell generation time is shorter than the time required for complete DNA replication; therefore, overlapping rounds of chromosome replication are required. Under these circumstances, the ori region DNA abundance exceeds the DNA abundance in the termination (ter) region. Here, high ori/ter ratios are found to persist in (p)ppGpp-deficient [(p)ppGpp(0)] cells over a wide range of balanced exponential growth rates determined by medium composition. Evidently, (p)ppGpp is necessary to maintain the usual correlation of slow DNA replication initiation with a low growth rate. Conversely, ori/ter ratios are lowered when cell growth is slowed by incrementally increasing even low constitutive basal levels of (p)ppGpp without stress, as if (p)ppGpp alone is sufficient for this response. There are several previous reports of (p)ppGpp inhibition of chromosomal DNA synthesis initiation that occurs with very high levels of (p)ppGpp that stop growth, as during the stringent starvation response or during serine hydroxamate treatment. This work suggests that low physiological levels of (p)ppGpp have significant functions in growing cells without stress through a mechanism involving negative supercoiling, which is likely mediated by (p)ppGpp regulation of DNA gyrase.
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spelling pubmed-70647772020-03-13 The Absence of (p)ppGpp Renders Initiation of Escherichia coli Chromosomal DNA Synthesis Independent of Growth Rates Fernández-Coll, Llorenç Maciag-Dorszynska, Monika Tailor, Krishma Vadia, Stephen Levin, Petra Anne Szalewska-Palasz, Agnieszka Cashel, Michael mBio Research Article The initiation of Escherichia coli chromosomal DNA replication starts with the oligomerization of the DnaA protein at repeat sequences within the origin (ori) region. The amount of ori DNA per cell directly correlates with the growth rate. During fast growth, the cell generation time is shorter than the time required for complete DNA replication; therefore, overlapping rounds of chromosome replication are required. Under these circumstances, the ori region DNA abundance exceeds the DNA abundance in the termination (ter) region. Here, high ori/ter ratios are found to persist in (p)ppGpp-deficient [(p)ppGpp(0)] cells over a wide range of balanced exponential growth rates determined by medium composition. Evidently, (p)ppGpp is necessary to maintain the usual correlation of slow DNA replication initiation with a low growth rate. Conversely, ori/ter ratios are lowered when cell growth is slowed by incrementally increasing even low constitutive basal levels of (p)ppGpp without stress, as if (p)ppGpp alone is sufficient for this response. There are several previous reports of (p)ppGpp inhibition of chromosomal DNA synthesis initiation that occurs with very high levels of (p)ppGpp that stop growth, as during the stringent starvation response or during serine hydroxamate treatment. This work suggests that low physiological levels of (p)ppGpp have significant functions in growing cells without stress through a mechanism involving negative supercoiling, which is likely mediated by (p)ppGpp regulation of DNA gyrase. American Society for Microbiology 2020-03-10 /pmc/articles/PMC7064777/ /pubmed/32156825 http://dx.doi.org/10.1128/mBio.03223-19 Text en https://doi.org/10.1128/AuthorWarrantyLicense.v1 This is a work of the U.S. Government and is not subject to copyright protection in the United States. Foreign copyrights may apply.
spellingShingle Research Article
Fernández-Coll, Llorenç
Maciag-Dorszynska, Monika
Tailor, Krishma
Vadia, Stephen
Levin, Petra Anne
Szalewska-Palasz, Agnieszka
Cashel, Michael
The Absence of (p)ppGpp Renders Initiation of Escherichia coli Chromosomal DNA Synthesis Independent of Growth Rates
title The Absence of (p)ppGpp Renders Initiation of Escherichia coli Chromosomal DNA Synthesis Independent of Growth Rates
title_full The Absence of (p)ppGpp Renders Initiation of Escherichia coli Chromosomal DNA Synthesis Independent of Growth Rates
title_fullStr The Absence of (p)ppGpp Renders Initiation of Escherichia coli Chromosomal DNA Synthesis Independent of Growth Rates
title_full_unstemmed The Absence of (p)ppGpp Renders Initiation of Escherichia coli Chromosomal DNA Synthesis Independent of Growth Rates
title_short The Absence of (p)ppGpp Renders Initiation of Escherichia coli Chromosomal DNA Synthesis Independent of Growth Rates
title_sort absence of (p)ppgpp renders initiation of escherichia coli chromosomal dna synthesis independent of growth rates
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7064777/
https://www.ncbi.nlm.nih.gov/pubmed/32156825
http://dx.doi.org/10.1128/mBio.03223-19
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