Temporal dynamics of base excision/single-strand break repair protein complex assembly/disassembly are modulated by the PARP/NAD+/SIRT6 axis
Christopher A. Koczor,
Kate M. Saville,
Joel F. Andrews,
Jennifer Clark,
Qingming Fang,
Jianfeng Li,
Rasha Q. Al-Rahahleh,
Md Ibrahim,
Steven McClellan,
Mikhail V. Makarov,
Marie E. Migaud,
Robert W. Sobol
Affiliations
Christopher A. Koczor
Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA; Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36604, USA
Kate M. Saville
Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA; Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36604, USA
Joel F. Andrews
Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA
Jennifer Clark
Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA; Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36604, USA
Qingming Fang
Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA; Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36604, USA
Jianfeng Li
Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA; Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36604, USA
Rasha Q. Al-Rahahleh
Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA; Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36604, USA
Md Ibrahim
Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA; Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36604, USA
Steven McClellan
Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA
Mikhail V. Makarov
Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA; Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36604, USA
Marie E. Migaud
Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA; Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36604, USA
Robert W. Sobol
Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA; Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36604, USA; Corresponding author
Summary: 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.
