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Replisome mechanics: lagging strand events that influence speed and processivity

The antiparallel structure of DNA requires lagging strand synthesis to proceed in the opposite direction of the replication fork. This imposes unique events that occur only on the lagging strand, such as primase binding to DnaB helicase, RNA synthesis, and SS B antigen (SSB) displacement during Okaz...

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Autores principales: Georgescu, Roxana E., Yao, Nina, Indiani, Chiara, Yurieva, Olga, O'Donnell, Mike E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4041431/
https://www.ncbi.nlm.nih.gov/pubmed/24829446
http://dx.doi.org/10.1093/nar/gku257
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author Georgescu, Roxana E.
Yao, Nina
Indiani, Chiara
Yurieva, Olga
O'Donnell, Mike E.
author_facet Georgescu, Roxana E.
Yao, Nina
Indiani, Chiara
Yurieva, Olga
O'Donnell, Mike E.
author_sort Georgescu, Roxana E.
collection PubMed
description The antiparallel structure of DNA requires lagging strand synthesis to proceed in the opposite direction of the replication fork. This imposes unique events that occur only on the lagging strand, such as primase binding to DnaB helicase, RNA synthesis, and SS B antigen (SSB) displacement during Okazaki fragment extension. Single-molecule and ensemble techniques are combined to examine the effect of lagging strand events on the Escherichia coli replisome rate and processivity. We find that primase activity lowers replisome processivity but only when lagging strand extension is inoperative. rNTPs also lower replisome processivity. However, the negative effects of primase and rNTPs on processivity are overcome by the extra grip on DNA provided by the lagging strand polymerases. Visualization of single molecules reveals that SSB accumulates at forks and may wrap extensive amounts of single-strand DNA. Interestingly SSB has an inter-strand positive effect on the rate of the leading strand based in its interaction with the replicase χ-subunit. Further, the lagging strand polymerase is faster than leading strand synthesis, indicating that replisome rate is limited by the helicase. Overall, lagging strand events that impart negative effects on the replisome are counterbalanced by the positive effects of SSB and additional sliding clamps during Okazaki fragment extension.
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spelling pubmed-40414312014-06-11 Replisome mechanics: lagging strand events that influence speed and processivity Georgescu, Roxana E. Yao, Nina Indiani, Chiara Yurieva, Olga O'Donnell, Mike E. Nucleic Acids Res Nucleic Acid Enzymes The antiparallel structure of DNA requires lagging strand synthesis to proceed in the opposite direction of the replication fork. This imposes unique events that occur only on the lagging strand, such as primase binding to DnaB helicase, RNA synthesis, and SS B antigen (SSB) displacement during Okazaki fragment extension. Single-molecule and ensemble techniques are combined to examine the effect of lagging strand events on the Escherichia coli replisome rate and processivity. We find that primase activity lowers replisome processivity but only when lagging strand extension is inoperative. rNTPs also lower replisome processivity. However, the negative effects of primase and rNTPs on processivity are overcome by the extra grip on DNA provided by the lagging strand polymerases. Visualization of single molecules reveals that SSB accumulates at forks and may wrap extensive amounts of single-strand DNA. Interestingly SSB has an inter-strand positive effect on the rate of the leading strand based in its interaction with the replicase χ-subunit. Further, the lagging strand polymerase is faster than leading strand synthesis, indicating that replisome rate is limited by the helicase. Overall, lagging strand events that impart negative effects on the replisome are counterbalanced by the positive effects of SSB and additional sliding clamps during Okazaki fragment extension. Oxford University Press 2014-06-01 2014-05-16 /pmc/articles/PMC4041431/ /pubmed/24829446 http://dx.doi.org/10.1093/nar/gku257 Text en © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research. http://creativecommons.org/licenses/by/3.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Nucleic Acid Enzymes
Georgescu, Roxana E.
Yao, Nina
Indiani, Chiara
Yurieva, Olga
O'Donnell, Mike E.
Replisome mechanics: lagging strand events that influence speed and processivity
title Replisome mechanics: lagging strand events that influence speed and processivity
title_full Replisome mechanics: lagging strand events that influence speed and processivity
title_fullStr Replisome mechanics: lagging strand events that influence speed and processivity
title_full_unstemmed Replisome mechanics: lagging strand events that influence speed and processivity
title_short Replisome mechanics: lagging strand events that influence speed and processivity
title_sort replisome mechanics: lagging strand events that influence speed and processivity
topic Nucleic Acid Enzymes
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4041431/
https://www.ncbi.nlm.nih.gov/pubmed/24829446
http://dx.doi.org/10.1093/nar/gku257
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