How PARP1 affects repair of CRISPR/Cas9 DNA breaks in dividing cells

PARP1 downregulation increased both NHEJ and MMEJ repair activities.

• Non-homologous end joining (NHEJ) often leads to mutagenic repair through insertions or deletions.
• Microhomology-mediated end joining (MMEJ) results in larger deletions due to end resection.
• Homologous recombination (HR) allows for precise sequence changes but is typically inefficient in many cell types.
• PARP1 downregulation did not affect HR while enhancing both NHEJ and MMEJ repair pathways.
• PARP1 overexpression reduced NHEJ and HR activity but did not impact MMEJ.
• Targeted modulation of PARP1 is associated with potential improvements in the precision of CRISPR-based genome editing.

Simplified