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Failure to degrade poly(ADP-ribose) causes increased sensitivity to cytotoxicity and early embryonic lethality

David W Koh1, Ann M Lawler, Marc F Poitras

  • 1Institute for Cell Engineering and Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.

Proceedings of the National Academy of Sciences of the United States of America
|December 14, 2004
PubMed

Insights

Disrupting the poly(ADP-ribose) glycohydrolase (PARG) gene causes embryonic lethality due to PAR accumulation. PARG is essential for embryonic development and protecting cells from genotoxic stress.

Area of Science:

  • Molecular Biology
  • Genetics
  • Developmental Biology

Background:

  • Poly(ADP-ribose) (PAR) metabolism is crucial for maintaining genomic stability in eukaryotes.
  • The enzyme poly(ADP-ribose) glycohydrolase (PARG) is responsible for degrading PAR.
  • The precise role of PARG in early development and stress response is not fully understood.

Purpose of the Study:

  • To investigate the consequences of PARG deficiency in mice.
  • To determine the impact of impaired PAR degradation on embryonic development and cellular stress responses.

Main Methods:

  • Generation of PARG-deficient mice through gene disruption.
  • Analysis of PARG null embryos and derived stem cell lines.
  • Assessment of PAR accumulation, apoptosis, and cellular viability under genotoxic stress and PARP inhibition.

Main Results:

  • PARG disruption leads to early embryonic lethality.
  • PARG null blastocysts accumulate PAR and undergo apoptosis.
  • Embryonic stem cells lacking PARG require PARP inhibition (benzamide) for survival.
  • PARG-deficient cells exhibit reduced growth and increased sensitivity to genotoxic agents after benzamide withdrawal.

Conclusions:

  • Failure to degrade PAR, due to PARG deficiency, has severe detrimental effects on embryonic development.
  • PARG plays a critical role in embryonic development.
  • PARG is essential for protecting cells against genotoxic stress.

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