PIF1 helicase promotes break‐induced replication in mammalian cells
Open Access
- 20 January 2021
- journal article
- research article
- Published by Springer Science and Business Media LLC in The EMBO Journal
- Vol. 40 (8), e104509
- https://doi.org/10.15252/embj.2020104509
Abstract
Break‐induced replication (BIR) is a specialized homologous‐recombination pathway for DNA double‐strand break (DSB) repair, which often induces genome instability. In this study, we establish EGFP‐based recombination reporters to systematically study BIR in mammalian cells and demonstrate an important role of human PIF1 helicase in promoting BIR. We show that at endonuclease cleavage sites, PIF1‐dependent BIR is used for homology‐initiated recombination requiring long track DNA synthesis, but not short track gene conversion (STGC). We also show that structure formation‐prone AT‐rich DNA sequences derived from common fragile sites (CFS‐ATs) induce BIR upon replication stress and oncogenic stress, and PCNA‐dependent loading of PIF1 onto collapsed/broken forks is critical for BIR activation. At broken replication forks, even STGC‐mediated repair of double‐ended DSBs depends on POLD3 and PIF1, revealing an unexpected mechanism of BIR activation upon replication stress that differs from the conventional BIR activation model requiring DSB end sensing at endonuclease‐generated breaks. Furthermore, loss of PIF1 is synthetically lethal with loss of FANCM, which is involved in protecting CFS‐ATs. The breast cancer‐associated PIF1 mutant L319P is defective in BIR, suggesting a direct link of BIR to oncogenic processes.Keywords
Funding Information
- Foundation for the National Institutes of Health (GM080677)
- National Cancer Institute (CA187052, CA197995, CA244912)
This publication has 86 references indexed in Scilit:
- Cdk1 uncouples CtIP-dependent resection and Rad51 filament formation during M-phase double-strand break repairThe Journal of cell biology, 2011
- Analysis of DNA double-strand break response and chromatin structure in mitosis using laser microirradiationNucleic Acids Research, 2010
- DNA damage signaling in response to double-strand breaks during mitosisThe Journal of cell biology, 2010
- Unwinding the functions of the Pif1 family helicasesDNA Repair, 2010
- The Carboxyl Terminus of Brca2 Links the Disassembly of Rad51 Complexes to Mitotic EntryCurrent Biology, 2009
- Genome instability: a mechanistic view of its causes and consequencesNature Reviews Genetics, 2008
- An AT-Rich Sequence in Human Common Fragile Site FRA16D Causes Fork Stalling and Chromosome Breakage in S. cerevisiaeMolecular Cell, 2007
- Oncogene-induced senescence is a DNA damage response triggered by DNA hyper-replicationNature, 2006
- Oncogene-induced senescence is part of the tumorigenesis barrier imposed by DNA damage checkpointsNature, 2006
- Correction of multi-gene deficiency in vivo using a single 'self-cleaving' 2A peptide–based retroviral vectorNature Biotechnology, 2004