Mismatch repair-independent increase in spontaneous mutagenesis in yeast lacking non-essential subunits of DNA polymerase ε.

Yeast DNA polymerase ε (Pol ε) is a highly accurate and processive enzyme that participates in nuclear DNA replication of the leading strand template. In addition to a large subunit (Pol2) harboring the polymerase and proofreading exonuclease active sites, Pol ε also has one essential subunit (Dpb2)...

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Autores principales: Anna Aksenova, Kirill Volkov, Jaroslaw Maceluch, Zachary F Pursell, Igor B Rogozin, Thomas A Kunkel, Youri I Pavlov, Erik Johansson
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Publicado: Public Library of Science (PLoS) 2010
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spelling oai:doaj.org-article:71e5bfc8f21d485e8204bf7838102d4d2021-11-18T06:19:18ZMismatch repair-independent increase in spontaneous mutagenesis in yeast lacking non-essential subunits of DNA polymerase ε.1553-73901553-740410.1371/journal.pgen.1001209https://doaj.org/article/71e5bfc8f21d485e8204bf7838102d4d2010-11-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21124948/pdf/?tool=EBIhttps://doaj.org/toc/1553-7390https://doaj.org/toc/1553-7404Yeast DNA polymerase ε (Pol ε) is a highly accurate and processive enzyme that participates in nuclear DNA replication of the leading strand template. In addition to a large subunit (Pol2) harboring the polymerase and proofreading exonuclease active sites, Pol ε also has one essential subunit (Dpb2) and two smaller, non-essential subunits (Dpb3 and Dpb4) whose functions are not fully understood. To probe the functions of Dpb3 and Dpb4, here we investigate the consequences of their absence on the biochemical properties of Pol ε in vitro and on genome stability in vivo. The fidelity of DNA synthesis in vitro by purified Pol2/Dpb2, i.e. lacking Dpb3 and Dpb4, is comparable to the four-subunit Pol ε holoenzyme. Nonetheless, deletion of DPB3 and DPB4 elevates spontaneous frameshift and base substitution rates in vivo, to the same extent as the loss of Pol ε proofreading activity in a pol2-4 strain. In contrast to pol2-4, however, the dpb3Δdpb4Δ does not lead to a synergistic increase of mutation rates with defects in DNA mismatch repair. The increased mutation rate in dpb3Δdpb4Δ strains is partly dependent on REV3, as well as the proofreading capacity of Pol δ. Finally, biochemical studies demonstrate that the absence of Dpb3 and Dpb4 destabilizes the interaction between Pol ε and the template DNA during processive DNA synthesis and during processive 3' to 5'exonucleolytic degradation of DNA. Collectively, these data suggest a model wherein Dpb3 and Dpb4 do not directly influence replication fidelity per se, but rather contribute to normal replication fork progression. In their absence, a defective replisome may more frequently leave gaps on the leading strand that are eventually filled by Pol ζ or Pol δ, in a post-replication process that generates errors not corrected by the DNA mismatch repair system.Anna AksenovaKirill VolkovJaroslaw MaceluchZachary F PursellIgor B RogozinThomas A KunkelYouri I PavlovErik JohanssonPublic Library of Science (PLoS)articleGeneticsQH426-470ENPLoS Genetics, Vol 6, Iss 11, p e1001209 (2010)
institution DOAJ
collection DOAJ
language EN
topic Genetics
QH426-470
spellingShingle Genetics
QH426-470
Anna Aksenova
Kirill Volkov
Jaroslaw Maceluch
Zachary F Pursell
Igor B Rogozin
Thomas A Kunkel
Youri I Pavlov
Erik Johansson
Mismatch repair-independent increase in spontaneous mutagenesis in yeast lacking non-essential subunits of DNA polymerase ε.
description Yeast DNA polymerase ε (Pol ε) is a highly accurate and processive enzyme that participates in nuclear DNA replication of the leading strand template. In addition to a large subunit (Pol2) harboring the polymerase and proofreading exonuclease active sites, Pol ε also has one essential subunit (Dpb2) and two smaller, non-essential subunits (Dpb3 and Dpb4) whose functions are not fully understood. To probe the functions of Dpb3 and Dpb4, here we investigate the consequences of their absence on the biochemical properties of Pol ε in vitro and on genome stability in vivo. The fidelity of DNA synthesis in vitro by purified Pol2/Dpb2, i.e. lacking Dpb3 and Dpb4, is comparable to the four-subunit Pol ε holoenzyme. Nonetheless, deletion of DPB3 and DPB4 elevates spontaneous frameshift and base substitution rates in vivo, to the same extent as the loss of Pol ε proofreading activity in a pol2-4 strain. In contrast to pol2-4, however, the dpb3Δdpb4Δ does not lead to a synergistic increase of mutation rates with defects in DNA mismatch repair. The increased mutation rate in dpb3Δdpb4Δ strains is partly dependent on REV3, as well as the proofreading capacity of Pol δ. Finally, biochemical studies demonstrate that the absence of Dpb3 and Dpb4 destabilizes the interaction between Pol ε and the template DNA during processive DNA synthesis and during processive 3' to 5'exonucleolytic degradation of DNA. Collectively, these data suggest a model wherein Dpb3 and Dpb4 do not directly influence replication fidelity per se, but rather contribute to normal replication fork progression. In their absence, a defective replisome may more frequently leave gaps on the leading strand that are eventually filled by Pol ζ or Pol δ, in a post-replication process that generates errors not corrected by the DNA mismatch repair system.
format article
author Anna Aksenova
Kirill Volkov
Jaroslaw Maceluch
Zachary F Pursell
Igor B Rogozin
Thomas A Kunkel
Youri I Pavlov
Erik Johansson
author_facet Anna Aksenova
Kirill Volkov
Jaroslaw Maceluch
Zachary F Pursell
Igor B Rogozin
Thomas A Kunkel
Youri I Pavlov
Erik Johansson
author_sort Anna Aksenova
title Mismatch repair-independent increase in spontaneous mutagenesis in yeast lacking non-essential subunits of DNA polymerase ε.
title_short Mismatch repair-independent increase in spontaneous mutagenesis in yeast lacking non-essential subunits of DNA polymerase ε.
title_full Mismatch repair-independent increase in spontaneous mutagenesis in yeast lacking non-essential subunits of DNA polymerase ε.
title_fullStr Mismatch repair-independent increase in spontaneous mutagenesis in yeast lacking non-essential subunits of DNA polymerase ε.
title_full_unstemmed Mismatch repair-independent increase in spontaneous mutagenesis in yeast lacking non-essential subunits of DNA polymerase ε.
title_sort mismatch repair-independent increase in spontaneous mutagenesis in yeast lacking non-essential subunits of dna polymerase ε.
publisher Public Library of Science (PLoS)
publishDate 2010
url https://doaj.org/article/71e5bfc8f21d485e8204bf7838102d4d
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