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Mechanism of Bidirectional Leading-Strand Synthesis Establishment at Eukaryotic DNA Replication Origins

DNA replication commences at eukaryotic replication origins following assembly and activation of bidirectional CMG helicases. Once activated, CMG unwinds the parental DNA duplex and DNA polymerase α-primase initiates synthesis on both template strands. By utilizing an origin-dependent replication sy...

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Detalles Bibliográficos
Autores principales: Aria, Valentina, Yeeles, Joseph T.P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Cell Press 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6344338/
https://www.ncbi.nlm.nih.gov/pubmed/30451148
http://dx.doi.org/10.1016/j.molcel.2018.10.019
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author Aria, Valentina
Yeeles, Joseph T.P.
author_facet Aria, Valentina
Yeeles, Joseph T.P.
author_sort Aria, Valentina
collection PubMed
description DNA replication commences at eukaryotic replication origins following assembly and activation of bidirectional CMG helicases. Once activated, CMG unwinds the parental DNA duplex and DNA polymerase α-primase initiates synthesis on both template strands. By utilizing an origin-dependent replication system using purified yeast proteins, we have mapped start sites for leading-strand replication. Synthesis is mostly initiated outside the origin sequence. Strikingly, rightward leading strands are primed left of the origin and vice versa. We show that each leading strand is established from a lagging-strand primer synthesized by the replisome on the opposite side of the origin. Preventing elongation of primers synthesized left of the origin blocked rightward leading strands, demonstrating that replisomes are interdependent for leading-strand synthesis establishment. The mechanism we reveal negates the need for dedicated leading-strand priming and necessitates a crucial role for the lagging-strand polymerase Pol δ in connecting the nascent leading strand with the advancing replisome.
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spelling pubmed-63443382019-01-28 Mechanism of Bidirectional Leading-Strand Synthesis Establishment at Eukaryotic DNA Replication Origins Aria, Valentina Yeeles, Joseph T.P. Mol Cell Article DNA replication commences at eukaryotic replication origins following assembly and activation of bidirectional CMG helicases. Once activated, CMG unwinds the parental DNA duplex and DNA polymerase α-primase initiates synthesis on both template strands. By utilizing an origin-dependent replication system using purified yeast proteins, we have mapped start sites for leading-strand replication. Synthesis is mostly initiated outside the origin sequence. Strikingly, rightward leading strands are primed left of the origin and vice versa. We show that each leading strand is established from a lagging-strand primer synthesized by the replisome on the opposite side of the origin. Preventing elongation of primers synthesized left of the origin blocked rightward leading strands, demonstrating that replisomes are interdependent for leading-strand synthesis establishment. The mechanism we reveal negates the need for dedicated leading-strand priming and necessitates a crucial role for the lagging-strand polymerase Pol δ in connecting the nascent leading strand with the advancing replisome. Cell Press 2019-01-17 /pmc/articles/PMC6344338/ /pubmed/30451148 http://dx.doi.org/10.1016/j.molcel.2018.10.019 Text en © 2018 MRC Laboratory of Molecular Biology http://creativecommons.org/licenses/by/4.0/ This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Aria, Valentina
Yeeles, Joseph T.P.
Mechanism of Bidirectional Leading-Strand Synthesis Establishment at Eukaryotic DNA Replication Origins
title Mechanism of Bidirectional Leading-Strand Synthesis Establishment at Eukaryotic DNA Replication Origins
title_full Mechanism of Bidirectional Leading-Strand Synthesis Establishment at Eukaryotic DNA Replication Origins
title_fullStr Mechanism of Bidirectional Leading-Strand Synthesis Establishment at Eukaryotic DNA Replication Origins
title_full_unstemmed Mechanism of Bidirectional Leading-Strand Synthesis Establishment at Eukaryotic DNA Replication Origins
title_short Mechanism of Bidirectional Leading-Strand Synthesis Establishment at Eukaryotic DNA Replication Origins
title_sort mechanism of bidirectional leading-strand synthesis establishment at eukaryotic dna replication origins
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6344338/
https://www.ncbi.nlm.nih.gov/pubmed/30451148
http://dx.doi.org/10.1016/j.molcel.2018.10.019
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