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Published on: January 31, 2018
PARP1-dependent DNA-protein crosslink repair
Zita Fábián1, Ellen S Kakulidis1,2, Ivo A Hendriks1
1The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200, Copenhagen, Denmark.
Poly(ADP-ribosyl)ation (PARylation) repairs toxic DNA-protein crosslinks (DPCs) via PARP1. This pathway is crucial for resolving topoisomerase 1-DNA cleavage complexes (TOP1ccs), preventing replication fork collapse.
Area of Science:
- Molecular Biology
- DNA Repair Mechanisms
- Biochemistry
Background:
- DNA-protein crosslinks (DPCs) are cytotoxic DNA lesions impeding DNA metabolism.
- Post-translational modifications (PTMs) like SUMOylation and ubiquitylation are known to aid DPC repair, but other PTMs' roles are unclear.
Purpose of the Study:
- To investigate the role of poly(ADP-ribosyl)ation (PARylation) in DNA-protein crosslink (DPC) repair.
- To elucidate the mechanism of DPC resolution and its connection to other DNA lesions.
Main Methods:
- Utilized Xenopus egg extracts to study DPC repair.
- Employed the Flp-nick system to analyze topoisomerase 1-DNA cleavage complexes (TOP1ccs).
- Investigated the roles of PARP1, ubiquitylation, and the proteasome in DPC resolution.
Main Results:
- Identified a novel DPC repair pathway mediated by PARP1.
- Demonstrated that PARP1-dependent PARylation targets DPCs for ubiquitylation and proteasomal degradation.
- Showed that PARP1 activity is essential for resolving TOP1ccs, preventing replication fork stalling and disassembly.
Conclusions:
- Uncovered a PARP1-orchestrated pathway for DPC repair independent of DNA replication.
- Established the critical role of PARP1 in resolving TOP1ccs, highlighting a link between DPC and TOP1cc repair.
- Suggests that the interplay between TOP1 poisons and PARP inhibitors may stem from this uncovered repair pathway.
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