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Timeless Interacts with PARP-1 to Promote Homologous Recombination Repair

Si Xie1, Oliver Mortusewicz2, Hoi Tang Ma3

  • 1School of Biomedical Sciences, The University of Hong Kong, Hong Kong.

Molecular Cell
|September 8, 2015
PubMed

Insights

Human Timeless protein interacts with PARP-1, aiding DNA repair. This interaction is crucial for recruiting Timeless to DNA damage sites and facilitating homologous recombination repair, independent of poly(ADP-ribosyl)ation.

Area of Science:

  • Molecular Biology
  • DNA Repair Mechanisms
  • Protein Interactions

Background:

  • Human Timeless protein is essential for DNA replication fork stability, S phase checkpoint activation, and sister chromatid cohesion.
  • The role of Timeless in DNA damage repair remains largely unknown.

Purpose of the Study:

  • To investigate the potential involvement of Human Timeless in DNA damage repair pathways.
  • To elucidate the interaction between Timeless and Poly(ADP-ribose) polymerase 1 (PARP-1).

Main Methods:

  • Co-immunoprecipitation assays to confirm protein-protein interactions.
  • X-ray crystallography to determine the structural basis of Timeless-PARP-1 binding.
  • Laser-induced DNA damage assays to observe protein recruitment to lesions.
  • Homologous recombination repair assays.

Main Results:

  • Timeless physically interacts with PARP-1, independent of poly(ADP-ribosyl)ation.
  • Crystal structures reveal the Timeless PAB domain specifically binds PARP-1.
  • Timeless recruitment to DNA damage sites requires PARP-1 but not poly(ADP-ribosyl)ation.
  • Timeless-PARP-1 interaction is essential for efficient homologous recombination repair.

Conclusions:

  • Timeless plays a significant role in DNA damage response and repair.
  • The interaction between Timeless and PARP-1 is a key component of DNA repair pathways, particularly homologous recombination.
  • This study reveals a novel function for Timeless in conjunction with PARP-1 in maintaining genomic stability.

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