Mammalian Exo1 encodes both structural and catalytic functions that play distinct roles in essential biological processes

Sonja Schaetzlein, Richard Chahwan, Elena Avdievich, Sergio Roa, Kaichun Wei, Robert L. Eoff, Rani S. Sellers, Alan B. Clark, Thomas A. Kunkelf, Matthew D. Scharff, Winfried Edelmann

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Mammalian Exonuclease 1 (EXO1) is an evolutionarily conserved, multifunctional exonuclease involved in DNA damage repair, replication, immunoglobulin diversity, meiosis, and telomere maintenance. It has been assumed that EXO1 participates in these processes primarily through its exonuclease activity, but recent studies also suggest that EXO1 has a structural function in the assembly of higher-order protein complexes. To dissect the enzymatic and nonenzymatic roles of EXO1 in the different biological processes in vivo, we generated an EXO1-E109K knockin (Exo1EK) mouse expressing a stable exonuclease-deficient protein and, for comparison, a fully EXO1-deficient (Exo1null) mouse. In contrast to Exo1null/null mice, Exo1EK/EK mice retained mismatch repair activity and displayed normal class switch recombination and meiosis. However, both Exo1-mutant lines showed defects in DNA damage response including DNA double-strand break repair (DSBR) through DNA end resection, chromosomal stability, and tumor suppression, indicating that the enzymatic function is required for those processes. On a transformation-related protein 53 (Trp53)-null background, the DSBR defect caused by the E109K mutation altered the tumor spectrum but did not affect the overall survival as compared with p53-Exo1null mice, whose defects in both DSBR and mismatch repair also compromised survival. The separation of these functions demonstrates the differential requirement for the structural function and nuclease activity of mammalian EXO1 in distinct DNA repair processes and tumorigenesis in vivo.

Original languageEnglish (US)
JournalProceedings of the National Academy of Sciences of the United States of America
Volume110
Issue number27
DOIs
StatePublished - Jul 2 2013

Fingerprint

Biological Phenomena
Exonucleases
DNA Repair
DNA Mismatch Repair
Meiosis
DNA Damage
Chromosomal Instability
Proteins
Double-Stranded DNA Breaks
Telomere
exodeoxyribonuclease I
Genetic Recombination
Immunoglobulins
Neoplasms
Carcinogenesis
Maintenance
Mutation

Keywords

  • Scaffold function
  • Somatic hypermuation
  • ssDNA

ASJC Scopus subject areas

  • General

Cite this

Mammalian Exo1 encodes both structural and catalytic functions that play distinct roles in essential biological processes. / Schaetzlein, Sonja; Chahwan, Richard; Avdievich, Elena; Roa, Sergio; Wei, Kaichun; Eoff, Robert L.; Sellers, Rani S.; Clark, Alan B.; Kunkelf, Thomas A.; Scharff, Matthew D.; Edelmann, Winfried.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 110, No. 27, 02.07.2013.

Research output: Contribution to journalArticle

Schaetzlein, Sonja ; Chahwan, Richard ; Avdievich, Elena ; Roa, Sergio ; Wei, Kaichun ; Eoff, Robert L. ; Sellers, Rani S. ; Clark, Alan B. ; Kunkelf, Thomas A. ; Scharff, Matthew D. ; Edelmann, Winfried. / Mammalian Exo1 encodes both structural and catalytic functions that play distinct roles in essential biological processes. In: Proceedings of the National Academy of Sciences of the United States of America. 2013 ; Vol. 110, No. 27.
@article{a73ada0bfa554739a1de52c9468de931,
title = "Mammalian Exo1 encodes both structural and catalytic functions that play distinct roles in essential biological processes",
abstract = "Mammalian Exonuclease 1 (EXO1) is an evolutionarily conserved, multifunctional exonuclease involved in DNA damage repair, replication, immunoglobulin diversity, meiosis, and telomere maintenance. It has been assumed that EXO1 participates in these processes primarily through its exonuclease activity, but recent studies also suggest that EXO1 has a structural function in the assembly of higher-order protein complexes. To dissect the enzymatic and nonenzymatic roles of EXO1 in the different biological processes in vivo, we generated an EXO1-E109K knockin (Exo1EK) mouse expressing a stable exonuclease-deficient protein and, for comparison, a fully EXO1-deficient (Exo1null) mouse. In contrast to Exo1null/null mice, Exo1EK/EK mice retained mismatch repair activity and displayed normal class switch recombination and meiosis. However, both Exo1-mutant lines showed defects in DNA damage response including DNA double-strand break repair (DSBR) through DNA end resection, chromosomal stability, and tumor suppression, indicating that the enzymatic function is required for those processes. On a transformation-related protein 53 (Trp53)-null background, the DSBR defect caused by the E109K mutation altered the tumor spectrum but did not affect the overall survival as compared with p53-Exo1null mice, whose defects in both DSBR and mismatch repair also compromised survival. The separation of these functions demonstrates the differential requirement for the structural function and nuclease activity of mammalian EXO1 in distinct DNA repair processes and tumorigenesis in vivo.",
keywords = "Scaffold function, Somatic hypermuation, ssDNA",
author = "Sonja Schaetzlein and Richard Chahwan and Elena Avdievich and Sergio Roa and Kaichun Wei and Eoff, {Robert L.} and Sellers, {Rani S.} and Clark, {Alan B.} and Kunkelf, {Thomas A.} and Scharff, {Matthew D.} and Winfried Edelmann",
year = "2013",
month = "7",
day = "2",
doi = "10.1073/pnas.1308512110",
language = "English (US)",
volume = "110",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
number = "27",

}

TY - JOUR

T1 - Mammalian Exo1 encodes both structural and catalytic functions that play distinct roles in essential biological processes

AU - Schaetzlein, Sonja

AU - Chahwan, Richard

AU - Avdievich, Elena

AU - Roa, Sergio

AU - Wei, Kaichun

AU - Eoff, Robert L.

AU - Sellers, Rani S.

AU - Clark, Alan B.

AU - Kunkelf, Thomas A.

AU - Scharff, Matthew D.

AU - Edelmann, Winfried

PY - 2013/7/2

Y1 - 2013/7/2

N2 - Mammalian Exonuclease 1 (EXO1) is an evolutionarily conserved, multifunctional exonuclease involved in DNA damage repair, replication, immunoglobulin diversity, meiosis, and telomere maintenance. It has been assumed that EXO1 participates in these processes primarily through its exonuclease activity, but recent studies also suggest that EXO1 has a structural function in the assembly of higher-order protein complexes. To dissect the enzymatic and nonenzymatic roles of EXO1 in the different biological processes in vivo, we generated an EXO1-E109K knockin (Exo1EK) mouse expressing a stable exonuclease-deficient protein and, for comparison, a fully EXO1-deficient (Exo1null) mouse. In contrast to Exo1null/null mice, Exo1EK/EK mice retained mismatch repair activity and displayed normal class switch recombination and meiosis. However, both Exo1-mutant lines showed defects in DNA damage response including DNA double-strand break repair (DSBR) through DNA end resection, chromosomal stability, and tumor suppression, indicating that the enzymatic function is required for those processes. On a transformation-related protein 53 (Trp53)-null background, the DSBR defect caused by the E109K mutation altered the tumor spectrum but did not affect the overall survival as compared with p53-Exo1null mice, whose defects in both DSBR and mismatch repair also compromised survival. The separation of these functions demonstrates the differential requirement for the structural function and nuclease activity of mammalian EXO1 in distinct DNA repair processes and tumorigenesis in vivo.

AB - Mammalian Exonuclease 1 (EXO1) is an evolutionarily conserved, multifunctional exonuclease involved in DNA damage repair, replication, immunoglobulin diversity, meiosis, and telomere maintenance. It has been assumed that EXO1 participates in these processes primarily through its exonuclease activity, but recent studies also suggest that EXO1 has a structural function in the assembly of higher-order protein complexes. To dissect the enzymatic and nonenzymatic roles of EXO1 in the different biological processes in vivo, we generated an EXO1-E109K knockin (Exo1EK) mouse expressing a stable exonuclease-deficient protein and, for comparison, a fully EXO1-deficient (Exo1null) mouse. In contrast to Exo1null/null mice, Exo1EK/EK mice retained mismatch repair activity and displayed normal class switch recombination and meiosis. However, both Exo1-mutant lines showed defects in DNA damage response including DNA double-strand break repair (DSBR) through DNA end resection, chromosomal stability, and tumor suppression, indicating that the enzymatic function is required for those processes. On a transformation-related protein 53 (Trp53)-null background, the DSBR defect caused by the E109K mutation altered the tumor spectrum but did not affect the overall survival as compared with p53-Exo1null mice, whose defects in both DSBR and mismatch repair also compromised survival. The separation of these functions demonstrates the differential requirement for the structural function and nuclease activity of mammalian EXO1 in distinct DNA repair processes and tumorigenesis in vivo.

KW - Scaffold function

KW - Somatic hypermuation

KW - ssDNA

UR - http://www.scopus.com/inward/record.url?scp=84879734618&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84879734618&partnerID=8YFLogxK

U2 - 10.1073/pnas.1308512110

DO - 10.1073/pnas.1308512110

M3 - Article

VL - 110

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 - 27

ER -