TY - JOUR
T1 - Endonuclease EEPD1 Is a gatekeeper for repair of stressed replication forks
AU - Kim, Hyun Suk
AU - Nickoloff, Jac A.
AU - Wu, Yuehan
AU - Williamson, Elizabeth A.
AU - Sidhu, Gurjit Singh
AU - Reinert, Brian L.
AU - Jaiswal, Aruna S.
AU - Srinivasan, Gayathri
AU - Patel, Bhavita
AU - Kong, Kimi
AU - Burma, Sandeep
AU - Lee, Suk Hee
AU - Hromas, Robert A.
N1 - Funding Information:
This work was supported by National Institutes of Health Grants R01GM109645, CA139429, and CA205224 (to R. H.); R01 CA152367 (to S. H. L.); R01 GM084020 (to J. A. N., E. A. W., and R. H.); and RO1CA149461, RO1CA197796, and R21CA202403 and the National Aeronautics and Space Administration Grant NNX16AD78G (to S. B.); and the Leukemia and Lymphoma Society Grants 6253-13 and 8995-14 and the Florida Bankhead-Coley program (to R. H.). The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
PY - 2017/2/17
Y1 - 2017/2/17
N2 - Replication is not as continuous as once thought, with DNA damage frequently stalling replication forks. Aberrant repair of stressed replication forks can result in cell death or genome instability and resulting transformation to malignancy. Stressed replication forks are most commonly repaired via homologous recombination (HR), which begins with 5′ end resection, mediated by exonuclease complexes, one of which contains Exo1.However, Exo1 requires free 5′-DNA ends upon which to act, and these are not commonly present in non-reversed stalled replication forks. To generate a free 5′ end, stalled replication forks must therefore be cleaved. Although several candidate endonucleases have been implicated in cleavage of stalled replication forks to permit end resection, the identity of such an endonuclease remains elusive. Here we show that the 5′-endonuclease EEPD1 cleaves replication forks at the junction between the lagging parental strand and the unreplicated DNA parental double strands. This cleavage creates the structure that Exo1 requires for 5′ end resection and HR initiation. We observed that EEPD1 and Exo1 interact constitutively, and Exo1 repairs stalled replication forks poorly without EEPD1. Thus, EEPD1 performs a gatekeeper function for replication fork repair by mediating the fork cleavage that permits initiation of HR-mediated repair and restart of stressed forks.
AB - Replication is not as continuous as once thought, with DNA damage frequently stalling replication forks. Aberrant repair of stressed replication forks can result in cell death or genome instability and resulting transformation to malignancy. Stressed replication forks are most commonly repaired via homologous recombination (HR), which begins with 5′ end resection, mediated by exonuclease complexes, one of which contains Exo1.However, Exo1 requires free 5′-DNA ends upon which to act, and these are not commonly present in non-reversed stalled replication forks. To generate a free 5′ end, stalled replication forks must therefore be cleaved. Although several candidate endonucleases have been implicated in cleavage of stalled replication forks to permit end resection, the identity of such an endonuclease remains elusive. Here we show that the 5′-endonuclease EEPD1 cleaves replication forks at the junction between the lagging parental strand and the unreplicated DNA parental double strands. This cleavage creates the structure that Exo1 requires for 5′ end resection and HR initiation. We observed that EEPD1 and Exo1 interact constitutively, and Exo1 repairs stalled replication forks poorly without EEPD1. Thus, EEPD1 performs a gatekeeper function for replication fork repair by mediating the fork cleavage that permits initiation of HR-mediated repair and restart of stressed forks.
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U2 - 10.1074/jbc.M116.758235
DO - 10.1074/jbc.M116.758235
M3 - Article
C2 - 28049724
AN - SCOPUS:85013491941
VL - 292
SP - 2795
EP - 2804
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 7
ER -