E2F1 and E2F2 contribute to the DNA damage response in neuronal cells

CASTILLO D.S.; OGARA M.F.; CANEPA E.T.; PREGI N.

Potrero de los Funes, San Luis, República Argentina

Congreso; XLVII REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN EN BIOQUÍMICA Y BIOLOGÍA MOLECULAR (SAIB); 2011

SOCIEDAD ARGENTINA DE INVESTIGACIÓN EN BIOQUÍMICA Y BIOLOGÍA MOLECULAR (SAIB)

The E2F transciption factors are key regulators of multiple cellularprocesses including proliferation, development and apoptosis. Inthe last years, E2F1 has been described to participate in the DNAdamage response, an event that requires its post-translationalmodification and subsequent protein stabilization. We havepreviously reported that the E2F1 and E2F2 genes are alsoregulated at the transcriptional level and become inducedfollowing different genotoxic stimuli (neocarzinostatin, H2O2 andUV) in human and murine neuronal cells. Consistently, here weshow that DNA damage increased E2F transcriptional activity 4-fold, as assessed by reporter assays. Our goal was to characterizeand evaluate the significance of E2F1 and E2F2 induction in themaintenance of genome integrity. Inhibition of the MAPK andATM/ATR pathways prevented the upregulation of E2F1 and E2F2mRNA levels in response to genotoxic stress. E2F1 and E2F2ablation using antisense oligonucleotides resulted in increasedlevels of gammaH2AX following DNA damage, as observed byimmunofluorescence microscopy. Moreover, clonogenic assaysshowed that cells with reduced E2F1 and E2F2 mRNA levels have33% and 59% diminished proliferative capacity after genotoxicstimuli, respectively.Our results suggest that the enhanced transcription of E2F1 andE2F2 plays a relevant role during the DNA damage response.