E2F1 AND E2F2 CONTRIBUTE TO THE DNA DAMAGE RESPONSE IN NEURONAL CELLS

CASTILLO DS; OGARA MF; CÁNEPA ET; PREGI N

Potrero de los Funes, San Luis

Congreso; XLVII Reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2011

SAIB

The E2F transciption factors are key regulators of multiple cellular processes including proliferation, development and apoptosis. In the last years, E2F1 has been described to participate in the DNA damage response, an event that requires its post-translational modification and subsequent protein stabilization. We have previously reported that the E2F1 and E2F2 genes are also regulated at the transcriptional level and become induced following different genotoxic stimuli (neocarzinostatin, H2O2 and UV) in human and murine neuronal cells. Consistently, here we show that DNA damage increased E2F transcriptional activity 4-fold, as assessed by reporter assays. Our goal was to characterize and evaluate the significance of E2F1 and E2F2 induction in the maintenance of genome integrity. Inhibition of the MAPK and ATM/ATR pathways prevented the upregulation of E2F1 and E2F2 mRNA levels in response to genotoxic stress. E2F1 and E2F2 ablation using antisense oligonucleotides resulted in increased levels of gamma H2AX following DNA damage, as observed by immunofluorescence microscopy. Moreover, clonogenic assays showed that cells with reduced E2F1 and E2F2 mRNA levels have 33% and 59% diminished proliferative capacity after genotoxic stimuli, respectively. Our results suggest that the enhanced transcription of E2F1 and E2F2 plays a relevant role during the DNA damage response.