The transcription factor E2F1 promotes dopamine-evoked neuronal apoptosis by a mechanism independent of transcriptional activation

J Neurochem. 2001 Jul;78(2):287-97. doi: 10.1046/j.1471-4159.2001.00402.x.

Abstract

The E2F1 transcription factor plays an important role in promoting neuronal apoptosis; however, it is not clear how E2F1 does this. Here we show that E2F1 is involved in dopamine (DA)-evoked apoptosis in cerebellar granule neurons (CGNs). E2F1 -/- CGNs and CGNs expressing an antisense E2F1 cDNA were significantly protected from DA-toxicity relative to controls. The neuronal protection was accompanied by significantly reduced caspase 3 activity. E2F1-mediated neuronal apoptosis did not require activation of gene transcription because: (1) ectopic expression of E2F1 or its mutants lacking the transactivation domain induced neuronal apoptosis, whereas an E2F1 mutant lacking the DNA-binding domain did not; (2) under all of these conditions, known E2F1 target genes including cyclin A, cdc2 and p19(ARF) were not induced; and (3) DA-evoked neuronal apoptosis was associated with up-regulated E2F1, but not transcription of its target genes. Finally, E2F1-mediated neuronal apoptosis was associated with reduced nuclear factor (NF)-kappaB DNA-binding activity. Taken together, these data suggest that E2F1 promotes DA-evoked caspase 3-dependent neuronal apoptosis by a mechanism independent of gene transactivation, and this may possibly occur through inhibition of anti-apoptotic genes including NF-kappaB.

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Apoptosis / physiology*
  • Caspase 3
  • Caspases / metabolism
  • Cell Cycle Proteins*
  • Cell Line
  • Cell Survival / drug effects
  • Cells, Cultured
  • Cerebellum / cytology
  • Cerebellum / physiology*
  • DNA, Antisense / pharmacology
  • DNA-Binding Proteins / metabolism
  • Dopamine / toxicity*
  • E2F Transcription Factors
  • E2F1 Transcription Factor
  • Genes, Reporter
  • Green Fluorescent Proteins
  • Humans
  • Luciferases / genetics
  • Luminescent Proteins / genetics
  • Mice
  • Mice, Knockout
  • Neurons / cytology*
  • Neurons / drug effects
  • Neurons / physiology*
  • Oxidopamine / toxicity
  • Recombinant Fusion Proteins / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transcription Factors / deficiency
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism*
  • Transcriptional Activation
  • Transfection

Substances

  • Cell Cycle Proteins
  • DNA, Antisense
  • DNA-Binding Proteins
  • E2F Transcription Factors
  • E2F1 Transcription Factor
  • E2F1 protein, human
  • E2f1 protein, mouse
  • Luminescent Proteins
  • Recombinant Fusion Proteins
  • Transcription Factors
  • Green Fluorescent Proteins
  • Oxidopamine
  • Luciferases
  • CASP3 protein, human
  • Casp3 protein, mouse
  • Caspase 3
  • Caspases
  • Dopamine