Human exonuclease 5 is a novel sliding exonuclease required for genome stability

Justin L Sparks; Rakesh Kumar; Mayank Singh; Marc S Wold; Tej K Pandita; Peter M Burgers

doi:10.1074/jbc.M112.422444

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Human exonuclease 5 is a novel sliding exonuclease required for genome stability

Journal article

Open access

Peer reviewed

Human exonuclease 5 is a novel sliding exonuclease required for genome stability

Justin L Sparks, Rakesh Kumar, Mayank Singh, Marc S Wold, Tej K Pandita and Peter M Burgers

The Journal of biological chemistry, Vol.287(51), pp.42773-42783

12/14/2012

DOI: 10.1074/jbc.M112.422444

PMCID: PMC3522276

PMID: 23095756

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Abstract

Previously, we characterized Saccharomyces cerevisiae exonuclease 5 (EXO5), which is required for mitochondrial genome maintenance. Here, we identify the human homolog (C1orf176; EXO5) that functions in the repair of nuclear DNA damage. Human EXO5 (hEXO5) contains an iron-sulfur cluster. It is a single-stranded DNA (ssDNA)-specific bidirectional exonuclease with a strong preference for 5'-ends. After loading at an ssDNA end, hEXO5 slides extensively along the ssDNA prior to cutting, hence the designation sliding exonuclease. However, the single-stranded binding protein human replication protein A (hRPA) restricts sliding and enforces a unique, species-specific 5'-directionality onto hEXO5. This specificity is lost with a mutant form of hRPA (hRPA-t11) that fails to interact with hEXO5. hEXO5 localizes to nuclear repair foci in response to DNA damage, and its depletion in human cells leads to an increased sensitivity to DNA-damaging agents, in particular interstrand cross-linking-inducing agents. Depletion of hEXO5 also results in an increase in spontaneous and damage-induced chromosome abnormalities including the frequency of triradial chromosomes, suggesting an additional defect in the resolution of stalled DNA replication forks in hEXO5-depleted cells.

Cross-Linking Reagents - pharmacology

Humans

DNA Repair - radiation effects

Molecular Sequence Data

Ultraviolet Rays

Chromosome Aberrations - drug effects

Biocatalysis - drug effects

Protein Binding - drug effects

Protein Binding - radiation effects

Conserved Sequence

Genomic Instability - drug effects

Exonucleases - metabolism

Biocatalysis - radiation effects

Protein Multimerization - radiation effects

Amino Acid Sequence

Chromosome Aberrations - radiation effects

Genomic Instability - radiation effects

DNA Repair - drug effects

DNA, Single-Stranded - metabolism

Replication Protein A - metabolism

Genome, Human - genetics

Sequence Homology, Amino Acid

Exonucleases - chemistry

Substrate Specificity - drug effects

Substrate Specificity - radiation effects

Iron-Sulfur Proteins - metabolism

Protein Multimerization - drug effects

Details

Title: Subtitle: Human exonuclease 5 is a novel sliding exonuclease required for genome stability
Creators: Justin L Sparks - Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
Rakesh Kumar
Mayank Singh
Marc S Wold
Tej K Pandita
Peter M Burgers
Resource Type: Journal article
Publication Details: The Journal of biological chemistry, Vol.287(51), pp.42773-42783
DOI: 10.1074/jbc.M112.422444
PMID: 23095756
PMCID: PMC3522276
NLM abbreviation: J Biol Chem
ISSN: 0021-9258
eISSN: 1083-351X
Publisher: United States
Grant note: R01 GM032431 / NIGMS NIH HHS R01 CA154320 / NCI NIH HHS CA129537 / NCI NIH HHS CA154320 / NCI NIH HHS U19A1091175 / PHS HHS R01 GM083970 / NIGMS NIH HHS GM083970 / NIGMS NIH HHS R01 CA123232 / NCI NIH HHS CA123232 / NCI NIH HHS R01 GM044721 / NIGMS NIH HHS GM44721 / NIGMS NIH HHS R01 CA129537 / NCI NIH HHS GM032431 / NIGMS NIH HHS
Language: English
Date published: 12/14/2012
Academic Unit: Radiation Oncology; Biochemistry and Molecular Biology
Record Identifier: 9984025248602771

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