Molecular basis for processing of topoisomerase 1-triggered DNA damage by Apn2/APE2

Jessica S. Williams; Jessica L. Wojtaszek; Denise C. Appel; Juno Krahn; Bret D. Wallace; Evan Walsh; Thomas A. Kunkel; R. Scott Williams

Cell Reports (Oct 2022)

Molecular basis for processing of topoisomerase 1-triggered DNA damage by Apn2/APE2

Jessica S. Williams,
Jessica L. Wojtaszek,
Denise C. Appel,
Juno Krahn,
Bret D. Wallace,
Evan Walsh,
Thomas A. Kunkel,
R. Scott Williams

Affiliations

Jessica S. Williams: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
Jessica L. Wojtaszek: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
Denise C. Appel: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
Juno Krahn: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
Bret D. Wallace: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
Evan Walsh: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
Thomas A. Kunkel: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA; Corresponding author
R. Scott Williams: Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA; Corresponding author

Journal volume & issue: Vol. 41, no. 1
p. 111448

Abstract

Read online

Summary: Topoisomerase 1 (Top1) incises DNA containing ribonucleotides to generate complex DNA lesions that are resolved by APE2 (Apn2 in yeast). How Apn2 engages and processes this DNA damage is unclear. Here, we report X-ray crystal structures and biochemical analysis of Apn2-DNA complexes to demonstrate how Apn2 frays and cleaves 3′ DNA termini via a wedging mechanism that facilitates 1–6 nucleotide endonucleolytic cleavages. APN2 deletion and DNA-wedge mutant Saccharomyces cerevisiae strains display mutator phenotypes, cell growth defects, and sensitivity to genotoxic stress in a ribonucleotide excision repair (RER)-defective background harboring a high density of Top1-incised ribonucleotides. Our data implicate a wedge-and-cut mechanism underpinning the broad-specificity Apn2 nuclease activity that mitigates mutagenic and genome instability phenotypes caused by Top1 incision at genomic ribonucleotides incorporated by DNA polymerase epsilon.

CP: molecular biology

Published in Cell Reports

ISSN: 2211-1247 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Science: Biology (General)
Website: http://www.cell.com/cell-reports/home

About the journal

Abstract

Keywords