Ets1 is required for p53 transcriptional activity in UV-induced apoptosis in embryonic stem cells

AUTOR(ES)

Xu, Dakang

FONTE

Oxford University Press

RESUMO

Embryonic stem (ES) cells contain a p53-dependent apoptosis mechanism to avoid the continued proliferation and differentiation of damaged cells. We show that mouse ES cells lacking Ets1 are deficient in their ability to undergo UV-induced apoptosis, similar to p53 null ES cells. In Ets1–/– ES cells, UV induction of the p53 regulated genes mdm2, perp, cyclin G and bax was decreased both at mRNA and protein levels. While p53 protein levels were unaltered in Ets1–/– cells, its ability to transactivate genes such as mdm2 and cyclin G was reduced. Furthermore, electrophoretic mobility shift assays and immunoprecipitations demonstrated that the presence of Ets1 was necessary for a CBP/p53 complex to be formed. Chromatin immunoprecipitations demonstrated that Ets1 was required for the formation of a stable p53–DNA complex under physiological conditions and activation of histone acetyltransferase activity. These data demonstrate that Ets1 is an essential component of a UV-responsive p53 transcriptional activation complex in ES cells and suggests that Ets1 may contribute to the specificity of p53-dependent gene transactivation in distinct cellular compartments.

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