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Regulation of PARP1 and its apoptotic variant activity by single-stranded DNA

Waghela Deeksha1, Suman Abhishek1, Jyotsnendu Giri2

  • 1Macromolecular Structural Biology Lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Sangareddy, India.

The FEBS Journal
|May 29, 2023
PubMed

Insights

Poly(ADP-ribose) polymerase 1 (PARP1) binds single-stranded DNA (ssDNA) via its Zn-fingers. PAR not only releases ssDNA from PARP1 but also inhibits its activity, impacting DNA repair and apoptosis.

Area of Science:

  • Molecular Biology
  • Genomics
  • Biochemistry

Background:

  • Poly(ADP-ribose) polymerase 1 (PARP1) is crucial for genomic stability, detecting DNA breaks and recruiting repair proteins.
  • Single-stranded DNA (ssDNA) can form during DNA replication/repair and, if abundant, may cause cell death.
  • The interaction between PARP1 and ssDNA has not been previously explored.

Purpose of the Study:

  • To investigate the role of PARP1's Zn-finger domains (ZnF1 and ZnF2) in recognizing and binding single-stranded DNA (ssDNA).
  • To elucidate how poly(ADP-ribose) (PAR) affects the interaction between PARP1 and ssDNA, and PARP1's activity.
  • To understand the mechanism of PARP1 cleavage during apoptosis and its relation to ssDNA binding.

Main Methods:

  • Biochemical assays to study PARP1's interaction with ssDNA.
  • Analysis of PARP1 domain function using specific fragments (e.g., PARP1ΔZnF1-2).
  • Investigating the effect of PAR on ssDNA-PARP1 binding and PARP1 activity.

Main Results:

  • PARP1's ZnF1 and ZnF2 domains mediate high-affinity binding to ssDNA.
  • PAR and ssDNA bind to distinct domains on PARP1.
  • PAR binding causes ssDNA release from PARP1 and inhibits ssDNA-dependent PARP1 activity.
  • The apoptotic fragment PARP1ΔZnF1-2 requires the DNA-bound ZnF1-ZnF2PARP1 fragment for ssDNA-dependent stimulation.

Conclusions:

  • PARP1's Zn-finger domains are critical for ssDNA recognition.
  • PAR acts as a negative regulator of ssDNA binding and activity of PARP1.
  • The interplay between PARP1 fragments and ssDNA is essential for regulating DNA repair and apoptosis.
Keywords:
DNA repairPARP1apoptosispoly-(ADP-ribose) polymerasessDNA

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