Senescence is generally defined as an irreversible state of G 1 cell cycle arrest in which
cells are refractory to growth factor stimulation. In mouse embryo fibroblasts (MEFs),
induction of senescence requires the presence ofp19 ARF and p53, as genetic ablation of
either of these genes allows escape from senescence and leads to immortalization. We
have developed a lentiviral vector that directs the synthesis of a p53-specific short hairpin
transcript, which mediates stable suppression of p53 expression through RNA interference …