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A low Smc flux avoids collisions and facilitates chromosome organization in Bacillus subtilis

SMC complexes are widely conserved ATP-powered DNA-loop-extrusion motors indispensable for organizing and faithfully segregating chromosomes. How SMC complexes translocate along DNA for loop extrusion and what happens when two complexes meet on the same DNA molecule is largely unknown. Revealing the...

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Autores principales: Anchimiuk, Anna, Lioy, Virginia S, Bock, Florian Patrick, Minnen, Anita, Boccard, Frederic, Gruber, Stephan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8357415/
https://www.ncbi.nlm.nih.gov/pubmed/34346312
http://dx.doi.org/10.7554/eLife.65467
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author Anchimiuk, Anna
Lioy, Virginia S
Bock, Florian Patrick
Minnen, Anita
Boccard, Frederic
Gruber, Stephan
author_facet Anchimiuk, Anna
Lioy, Virginia S
Bock, Florian Patrick
Minnen, Anita
Boccard, Frederic
Gruber, Stephan
author_sort Anchimiuk, Anna
collection PubMed
description SMC complexes are widely conserved ATP-powered DNA-loop-extrusion motors indispensable for organizing and faithfully segregating chromosomes. How SMC complexes translocate along DNA for loop extrusion and what happens when two complexes meet on the same DNA molecule is largely unknown. Revealing the origins and the consequences of SMC encounters is crucial for understanding the folding process not only of bacterial, but also of eukaryotic chromosomes. Here, we uncover several factors that influence bacterial chromosome organization by modulating the probability of such clashes. These factors include the number, the strength, and the distribution of Smc loading sites, the residency time on the chromosome, the translocation rate, and the cellular abundance of Smc complexes. By studying various mutants, we show that these parameters are fine-tuned to reduce the frequency of encounters between Smc complexes, presumably as a risk mitigation strategy. Mild perturbations hamper chromosome organization by causing Smc collisions, implying that the cellular capacity to resolve them is limited. Altogether, we identify mechanisms that help to avoid Smc collisions and their resolution by Smc traversal or other potentially risky molecular transactions.
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spelling pubmed-83574152021-08-13 A low Smc flux avoids collisions and facilitates chromosome organization in Bacillus subtilis Anchimiuk, Anna Lioy, Virginia S Bock, Florian Patrick Minnen, Anita Boccard, Frederic Gruber, Stephan eLife Chromosomes and Gene Expression SMC complexes are widely conserved ATP-powered DNA-loop-extrusion motors indispensable for organizing and faithfully segregating chromosomes. How SMC complexes translocate along DNA for loop extrusion and what happens when two complexes meet on the same DNA molecule is largely unknown. Revealing the origins and the consequences of SMC encounters is crucial for understanding the folding process not only of bacterial, but also of eukaryotic chromosomes. Here, we uncover several factors that influence bacterial chromosome organization by modulating the probability of such clashes. These factors include the number, the strength, and the distribution of Smc loading sites, the residency time on the chromosome, the translocation rate, and the cellular abundance of Smc complexes. By studying various mutants, we show that these parameters are fine-tuned to reduce the frequency of encounters between Smc complexes, presumably as a risk mitigation strategy. Mild perturbations hamper chromosome organization by causing Smc collisions, implying that the cellular capacity to resolve them is limited. Altogether, we identify mechanisms that help to avoid Smc collisions and their resolution by Smc traversal or other potentially risky molecular transactions. eLife Sciences Publications, Ltd 2021-08-04 /pmc/articles/PMC8357415/ /pubmed/34346312 http://dx.doi.org/10.7554/eLife.65467 Text en © 2021, Anchimiuk et al https://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited.
spellingShingle Chromosomes and Gene Expression
Anchimiuk, Anna
Lioy, Virginia S
Bock, Florian Patrick
Minnen, Anita
Boccard, Frederic
Gruber, Stephan
A low Smc flux avoids collisions and facilitates chromosome organization in Bacillus subtilis
title A low Smc flux avoids collisions and facilitates chromosome organization in Bacillus subtilis
title_full A low Smc flux avoids collisions and facilitates chromosome organization in Bacillus subtilis
title_fullStr A low Smc flux avoids collisions and facilitates chromosome organization in Bacillus subtilis
title_full_unstemmed A low Smc flux avoids collisions and facilitates chromosome organization in Bacillus subtilis
title_short A low Smc flux avoids collisions and facilitates chromosome organization in Bacillus subtilis
title_sort low smc flux avoids collisions and facilitates chromosome organization in bacillus subtilis
topic Chromosomes and Gene Expression
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8357415/
https://www.ncbi.nlm.nih.gov/pubmed/34346312
http://dx.doi.org/10.7554/eLife.65467
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