Repression of Puma by scratch2 is required for neuronal survival during embryonic development

Cell Death Differ. 2011 Jul;18(7):1196-207. doi: 10.1038/cdd.2010.190. Epub 2011 Jan 21.

Abstract

Although Snail factors promote cell survival in development and cancer, the tumor-suppressor p53 promotes apoptosis in response to stress. p53 and Snail2 act antagonistically to regulate p53 upregulated modulator of apoptosis (Puma) and cell death in hematopoietic progenitors following DNA damage. Here, we show that this relationship is conserved in the developing nervous system in which Snail genes are excluded from vertebrate neurons and they are substituted by Scratch, a related but independent neural-specific factor. The transcription of scratch2 is induced directly by p53 after DNA damage to repress puma, thereby antagonizing p53-mediated apoptosis. In addition, we show that scratch2 is required for newly differentiated neurons to survive by maintaining Puma levels low during normal embryonic development in the absence of damage. scratch2 knockdown in zebrafish embryos leads to neuronal death through the activation of the intrinsic and extrinsic apoptotic pathways. To compensate for neuronal loss, the proliferation of neuronal precursors increases in scratch2-deficient embryos, reminiscent of the activation of progenitor/stem cell proliferation after damage-induced apoptosis. Our data indicate that the regulatory loop linking p53/Puma with Scratch is active in the vertebrate nervous system, not only controlling cell death in response to damage but also during normal embryonic development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis Regulatory Proteins / metabolism*
  • DNA Damage
  • Embryonic Development
  • Gene Knockdown Techniques
  • Nervous System / embryology
  • Neurons / cytology
  • Neurons / metabolism*
  • Proto-Oncogene Proteins / metabolism*
  • Snail Family Transcription Factors
  • Transcription Factors / antagonists & inhibitors
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Tumor Suppressor Protein p53 / antagonists & inhibitors
  • Tumor Suppressor Protein p53 / metabolism
  • Zebrafish / embryology
  • Zebrafish / metabolism
  • Zebrafish Proteins / antagonists & inhibitors
  • Zebrafish Proteins / genetics
  • Zebrafish Proteins / metabolism*

Substances

  • Apoptosis Regulatory Proteins
  • Proto-Oncogene Proteins
  • Snail Family Transcription Factors
  • Transcription Factors
  • Tumor Suppressor Protein p53
  • Zebrafish Proteins
  • bbc3 protein, zebrafish
  • scrt2 protein, zebrafish
  • snai1b protein, zebrafish