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Yeast As a Chassis for Developing Functional Assays to Study Human P53
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Regulation of p53 by Mdm2 E3 ligase function is dispensable in embryogenesis and development, but essential in

Laura A Tollini1, Aiwen Jin2, Jikyoung Park2

  • 1Department of Radiation Oncology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7512, USA; Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7512, USA; Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7512, USA.

Cancer Cell
|August 14, 2014
PubMed

Insights

The Mdm2 E3 ligase function is not essential for normal p53 regulation in mice. Disrupting this ligase activity leads to p53 accumulation but low activity, except under stress, revealing therapeutic insights.

Area of Science:

  • Molecular Biology
  • Cancer Biology
  • Genetics

Background:

  • Mdm2 E3 ubiquitin ligase is the primary regulator of p53 stability.
  • The in vivo significance of Mdm2's E3 ligase function for p53 regulation remains unclear.

Purpose of the Study:

  • To investigate the in vivo necessity of Mdm2's E3 ligase activity for p53 regulation.
  • To determine the physiological consequences of inactivating Mdm2's E3 ligase function.

Main Methods:

  • Generation of Mdm2(Y487A) knockin mice to specifically inactivate E3 ligase function.
  • Assessment of p53 levels, transcriptional activity, and stress responses in Mdm2(Y487A/Y487A) mice.

Main Results:

  • Mdm2(Y487A/Y487A) mice were viable and developed normally, indicating Mdm2 E3 ligase activity is not essential for normal development.
  • Inactivation of Mdm2 E3 ligase led to p53 accumulation but low basal transcriptional activity.
  • Mice exhibited hyperactive p53 and p53-dependent mortality upon exposure to sublethal stress.

Conclusions:

  • Mdm2 E3 ligase function may be dispensable for basal p53 regulation.
  • The p53 pathway's response to stress is critically dependent on Mdm2 E3 ligase activity.
  • Findings offer new perspectives for therapeutic targeting of the Mdm2-p53 pathway in cancer.

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