A possible mechanism for exonuclease 1-independent eukaryotic mismatch repair

Farid A. Kadyrov, Jochen Genschel, Yanan Fang, Elisabeth Penland, Winfried Edelmann, Paul Modrich

Research output: Contribution to journalArticle

83 Citations (Scopus)

Abstract

Mismatch repair contributes to genetic stability, and inactivation of the mammalian pathway leads to tumor development. Mismatch correction occurs by an excision-repair mechanism and has been shown to depend on the 5′ to 3′ hydrolytic activity exonuclease 1 (Exo1) in eukaryotic cells. However, genetic and biochemical studies have indicated that one or more Exo1-independent modes of mismatch repair also exist. We have analyzed repair of nicked circular heteroduplex DNA in extracts of Exo1-deficient mouse embryo fibroblast cells. Exo1-independent repair under these conditions is MutLα-dependent and requires functional integrity of the MutLα endonuclease metal-binding motif. In contrast to the Exo1-dependent reaction, we have been unable to detect a gapped excision intermediate in Exo1-deficient extracts when repair DNA synthesis is blocked. A possible explanation for this finding has been provided by analysis of a purified system comprised of MutSα, MutLα, replication factor C, proliferating cell nuclear antigen, replication protein A, and DNA polymerase δ that supports Exo1-independent repair in vitro. Repair in this system depends on MutLα incision of the nicked heteroduplex strand and dNTP-dependent synthesis-driven displacement of a DNA segment spanning the mismatch. Such a mechanism may account, at least in part, for the Exo1-independent repair that occurs in eukaryotic cells, and hence the modest cancer predisposition of Exo1-deficient mammalian cells.

Original languageEnglish (US)
Pages (from-to)8495-8500
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume106
Issue number21
DOIs
StatePublished - May 26 2009

Fingerprint

DNA Mismatch Repair
Eukaryotic Cells
DNA Repair
Replication Protein C
Nucleic Acid Heteroduplexes
Replication Protein A
Circular DNA
exodeoxyribonuclease I
Endonucleases
Proliferating Cell Nuclear Antigen
DNA-Directed DNA Polymerase
Molecular Biology
Neoplasms
Embryonic Structures
Fibroblasts
Metals
DNA

Keywords

  • Cancer
  • DNA polymerase
  • DNA repair
  • Strand displacment

ASJC Scopus subject areas

  • General

Cite this

A possible mechanism for exonuclease 1-independent eukaryotic mismatch repair. / Kadyrov, Farid A.; Genschel, Jochen; Fang, Yanan; Penland, Elisabeth; Edelmann, Winfried; Modrich, Paul.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 106, No. 21, 26.05.2009, p. 8495-8500.

Research output: Contribution to journalArticle

@article{710fde7c6d384fd3b8b35f0cb798203e,
title = "A possible mechanism for exonuclease 1-independent eukaryotic mismatch repair",
abstract = "Mismatch repair contributes to genetic stability, and inactivation of the mammalian pathway leads to tumor development. Mismatch correction occurs by an excision-repair mechanism and has been shown to depend on the 5′ to 3′ hydrolytic activity exonuclease 1 (Exo1) in eukaryotic cells. However, genetic and biochemical studies have indicated that one or more Exo1-independent modes of mismatch repair also exist. We have analyzed repair of nicked circular heteroduplex DNA in extracts of Exo1-deficient mouse embryo fibroblast cells. Exo1-independent repair under these conditions is MutLα-dependent and requires functional integrity of the MutLα endonuclease metal-binding motif. In contrast to the Exo1-dependent reaction, we have been unable to detect a gapped excision intermediate in Exo1-deficient extracts when repair DNA synthesis is blocked. A possible explanation for this finding has been provided by analysis of a purified system comprised of MutSα, MutLα, replication factor C, proliferating cell nuclear antigen, replication protein A, and DNA polymerase δ that supports Exo1-independent repair in vitro. Repair in this system depends on MutLα incision of the nicked heteroduplex strand and dNTP-dependent synthesis-driven displacement of a DNA segment spanning the mismatch. Such a mechanism may account, at least in part, for the Exo1-independent repair that occurs in eukaryotic cells, and hence the modest cancer predisposition of Exo1-deficient mammalian cells.",
keywords = "Cancer, DNA polymerase, DNA repair, Strand displacment",
author = "Kadyrov, {Farid A.} and Jochen Genschel and Yanan Fang and Elisabeth Penland and Winfried Edelmann and Paul Modrich",
year = "2009",
month = "5",
day = "26",
doi = "10.1073/pnas.0903654106",
language = "English (US)",
volume = "106",
pages = "8495--8500",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
number = "21",

}

TY - JOUR

T1 - A possible mechanism for exonuclease 1-independent eukaryotic mismatch repair

AU - Kadyrov, Farid A.

AU - Genschel, Jochen

AU - Fang, Yanan

AU - Penland, Elisabeth

AU - Edelmann, Winfried

AU - Modrich, Paul

PY - 2009/5/26

Y1 - 2009/5/26

N2 - Mismatch repair contributes to genetic stability, and inactivation of the mammalian pathway leads to tumor development. Mismatch correction occurs by an excision-repair mechanism and has been shown to depend on the 5′ to 3′ hydrolytic activity exonuclease 1 (Exo1) in eukaryotic cells. However, genetic and biochemical studies have indicated that one or more Exo1-independent modes of mismatch repair also exist. We have analyzed repair of nicked circular heteroduplex DNA in extracts of Exo1-deficient mouse embryo fibroblast cells. Exo1-independent repair under these conditions is MutLα-dependent and requires functional integrity of the MutLα endonuclease metal-binding motif. In contrast to the Exo1-dependent reaction, we have been unable to detect a gapped excision intermediate in Exo1-deficient extracts when repair DNA synthesis is blocked. A possible explanation for this finding has been provided by analysis of a purified system comprised of MutSα, MutLα, replication factor C, proliferating cell nuclear antigen, replication protein A, and DNA polymerase δ that supports Exo1-independent repair in vitro. Repair in this system depends on MutLα incision of the nicked heteroduplex strand and dNTP-dependent synthesis-driven displacement of a DNA segment spanning the mismatch. Such a mechanism may account, at least in part, for the Exo1-independent repair that occurs in eukaryotic cells, and hence the modest cancer predisposition of Exo1-deficient mammalian cells.

AB - Mismatch repair contributes to genetic stability, and inactivation of the mammalian pathway leads to tumor development. Mismatch correction occurs by an excision-repair mechanism and has been shown to depend on the 5′ to 3′ hydrolytic activity exonuclease 1 (Exo1) in eukaryotic cells. However, genetic and biochemical studies have indicated that one or more Exo1-independent modes of mismatch repair also exist. We have analyzed repair of nicked circular heteroduplex DNA in extracts of Exo1-deficient mouse embryo fibroblast cells. Exo1-independent repair under these conditions is MutLα-dependent and requires functional integrity of the MutLα endonuclease metal-binding motif. In contrast to the Exo1-dependent reaction, we have been unable to detect a gapped excision intermediate in Exo1-deficient extracts when repair DNA synthesis is blocked. A possible explanation for this finding has been provided by analysis of a purified system comprised of MutSα, MutLα, replication factor C, proliferating cell nuclear antigen, replication protein A, and DNA polymerase δ that supports Exo1-independent repair in vitro. Repair in this system depends on MutLα incision of the nicked heteroduplex strand and dNTP-dependent synthesis-driven displacement of a DNA segment spanning the mismatch. Such a mechanism may account, at least in part, for the Exo1-independent repair that occurs in eukaryotic cells, and hence the modest cancer predisposition of Exo1-deficient mammalian cells.

KW - Cancer

KW - DNA polymerase

KW - DNA repair

KW - Strand displacment

UR - http://www.scopus.com/inward/record.url?scp=66649124883&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=66649124883&partnerID=8YFLogxK

U2 - 10.1073/pnas.0903654106

DO - 10.1073/pnas.0903654106

M3 - Article

VL - 106

SP - 8495

EP - 8500

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 21

ER -