Related Experiment Video

Updated: Sep 29, 2025

Strand-Specific Analysis of Proteins at Replicating DNA Strands by Enrichment and Sequencing of Protein-Associated Nascent DNA Method
08:53

Strand-Specific Analysis of Proteins at Replicating DNA Strands by Enrichment and Sequencing of Protein-Associated Nascent DNA Method

Published on: May 2, 2025

513

PARP inhibition impedes the maturation of nascent DNA strands during DNA replication

Alina Vaitsiankova1, Kamila Burdova1, Margarita Sobol2

  • 1Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK.

Nature Structural & Molecular Biology
|March 25, 2022
PubMed

Insights

Poly(ADP-ribose) polymerase 1 (PARP1) inhibitors impair DNA replication by hindering Okazaki fragment maturation. This leads to DNA strand breaks and reduced cell survival, particularly when FEN1 nuclease is absent.

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • Poly(ADP-ribose) polymerase 1 (PARP1) is involved in DNA replication and repair.
  • Unligated Okazaki fragments and replication intermediates are potential sources of DNA damage upon PARP inhibition.

Purpose of the Study:

  • To investigate the role of PARP1 activity in DNA replication and the impact of PARP inhibitors on nascent DNA strand integrity.
  • To determine if FEN1 deficiency exacerbates the effects of PARP inhibition on DNA replication.

Main Methods:

  • Measuring PARP1 activity in chicken and human cells, including FEN1-deficient cells.
  • Treating cells with a PARP inhibitor and assessing nascent DNA strand integrity.
  • Analyzing DNA strand breaks and gaps using molecular techniques.

Main Results:

  • PARP1 activity is elevated in S phase cells, especially behind replication forks, and is further increased in FEN1-deficient cells.
  • PARP inhibition reduces nascent DNA strand integrity in both wild-type and FEN1-deficient cells.
  • FEN1 deficiency amplifies the DNA damage caused by PARP inhibitors, manifesting as increased single-strand nicks and gaps.

Conclusions:

  • PARP inhibitors disrupt the maturation of nascent DNA strands during replication.
  • Unligated Okazaki fragments and nascent strand discontinuities contribute to the cytotoxic effects of PARP inhibitors.
  • FEN1 plays a role in mitigating PARP inhibitor-induced DNA damage.

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