Metnase mediates loading of exonuclease 1 onto single strand overhang DNA for end resection at stalled replication forks

Hyun Suk Kim, Elizabeth A. Williamson, Jac A. Nickoloff, Robert A. Hromas, Suk-Hee Lee

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Stalling at DNA replication forks generates stretches of singlestranded (ss) DNA on both strands that are exposed to nucleolytic degradation, potentially compromising genome stability. One enzyme crucial for DNA replication fork repair and restart of stalled forks in human is Metnase (also known as SETMAR), a chimeric fusion protein consisting of a su(var)3-9, enhancer-of-zeste and trithorax (SET) histone methylase and transposase nuclease domain. We previously showed that Metnase possesses a unique fork cleavage activity necessary for its function in replication restart and that its SET domain is essential for recovery from hydroxyurea-inducedDNAdamage. However, its exact role in replication restart is unclear. In this study, we show that Metnase associates with exonuclease 1 (Exo1), a 5'-exonuclease crucial for 5'-end resection to mediateDNAprocessing at stalled forks. Metnase DNA cleavage activity was not required for Exo1 5'-exonuclease activity on the lagging strand daughter DNA, but its DNA binding activity mediated loading of Exo1 onto ssDNA overhangs. Metnase-induced enhancement of Exo1-mediated DNA strand resection required the presence of these overhangs but did not require Metnase's DNA cleavage activity. These results suggest that Metnase enhances Exo1-mediated exonuclease activity on the lagging strand DNA by facilitating Exo1 loading onto a single strand gap at the stalled replication fork.

Original languageEnglish (US)
Pages (from-to)1414-1425
Number of pages12
JournalJournal of Biological Chemistry
Volume292
Issue number4
DOIs
StatePublished - Jan 27 2017

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DNA
Phosphodiesterase I
DNA Cleavage
DNA Replication
Exodeoxyribonucleases
Transposases
Exonucleases
Hydroxyurea
Genomic Instability
exodeoxyribonuclease I
Repair
Enzymes
Fusion reactions
Genes
Recovery
Degradation
Proteins

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Metnase mediates loading of exonuclease 1 onto single strand overhang DNA for end resection at stalled replication forks. / Kim, Hyun Suk; Williamson, Elizabeth A.; Nickoloff, Jac A.; Hromas, Robert A.; Lee, Suk-Hee.

In: Journal of Biological Chemistry, Vol. 292, No. 4, 27.01.2017, p. 1414-1425.

Research output: Contribution to journalArticle

Kim, Hyun Suk ; Williamson, Elizabeth A. ; Nickoloff, Jac A. ; Hromas, Robert A. ; Lee, Suk-Hee. / Metnase mediates loading of exonuclease 1 onto single strand overhang DNA for end resection at stalled replication forks. In: Journal of Biological Chemistry. 2017 ; Vol. 292, No. 4. pp. 1414-1425.
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