Related Experiment Video
Updated: Oct 14, 2025

Laser Microirradiation to Study In Vivo Cellular Responses to Simple and Complex DNA Damage
Published on: January 31, 2018
Temporal dynamics of base excision/single-strand break repair protein complex assembly/disassembly are modulated by
Christopher A Koczor1, Kate M Saville1, Joel F Andrews2
1Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA; Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36604, USA.
Abstract:
Assembly and disassembly of DNA repair protein complexes at DNA damage sites are essential for maintaining genomic integrity. Investigating factors coordinating assembly of the base excision repair (BER) proteins DNA polymerase β (Polβ) and XRCC1 to DNA lesion sites identifies a role for Polβ in regulating XRCC1 disassembly from DNA repair complexes and, conversely, demonstrates Polβ's dependence on XRCC1 for complex assembly. LivePAR, a genetically encoded probe for live-cell imaging of poly(ADP-ribose) (PAR), reveals that Polβ and XRCC1 require PAR for repair-complex assembly, with PARP1 and PARP2 playing unique roles in complex dynamics. Further, BER complex assembly is modulated by attenuation/augmentation of NAD+ biosynthesis. Finally, SIRT6 does not modulate PARP1 or PARP2 activation but does regulate XRCC1 recruitment, leading to diminished Polβ abundance at sites of DNA damage. These findings highlight coordinated yet independent roles for PARP1, PARP2, and SIRT6 and their regulation by NAD+ bioavailability to facilitate BER.
Related Concept Videos
Long-patch Base Excision Repair
Restarting Stalled Replication Forks
DNA Damage can Stall the Cell Cycle
Base Excision Repair
Nucleotide Excision Repair
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
Base-pairing and DNA Repair

