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Regulation of E2F1-induced apoptosis by the nucleolar protein RRP1B

Jason C Paik1, Bing Wang, Kang Liu

  • 1Division of Hematology/Oncology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.

The Journal of Biological Chemistry
|December 31, 2009
PubMed

Insights

The transcription factor E2F1 targets the nucleolar protein RRP1B, which is crucial for E2F1-induced apoptosis. DNA damage activates RRP1B, promoting cell death through E2F1 target genes.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Cancer Research

Background:

  • Cellular proliferation is tightly regulated by E2F transcription factors, with their dysregulation being a hallmark of cancer.
  • The E2F1 protein paradoxically induces apoptosis, but the precise mechanisms remain unclear.

Purpose of the Study:

  • To identify E2F1-specific transcriptional targets.
  • To elucidate the role of RRP1B in E2F1-mediated apoptosis and its regulation by DNA damage.

Main Methods:

  • Promoter characterization and analysis of RRP1B gene expression.
  • Investigation of RRP1B's role in apoptosis induction by DNA-damaging agents.
  • Analysis of protein-protein interactions between RRP1B and E2F1.

Main Results:

  • RRP1B was identified as a novel, E2F1-specific transcriptional target with a promoter selectively responsive to E2F1.
  • RRP1B expression is induced by DNA-damaging agents, correlating with E2F1 activation.
  • RRP1B is essential for the expression of proapoptotic E2F1 target genes and DNA damage-induced apoptosis.
  • RRP1B forms complexes with E2F1 on target gene promoters, localized within the nucleolus and nucleoplasm.

Conclusions:

  • E2F1 utilizes its transcriptional target RRP1B to activate downstream apoptosis-inducing genes.
  • Nucleolar proteins, like RRP1B, play a significant, previously underappreciated role in transcriptional regulation.
  • RRP1B is a key mediator of E2F1's proapoptotic function, particularly in response to DNA damage.

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