Figure 3.
Sustained PI(3)K–PKB signalling or nuclear retention of cyclin D1 induces bypass of senescence. (a) Colony formation assay of primary MEFs infected with the indicated retroviral constructs. Immortalizing efficiency controls are p53kd MEFs stained after 1 or 3 weeks. (b) Growth curves of various depicted immortalizing constructs versus wild-type cyclin D1 infected MEFs. Overexpression of p53kd or control vector are positive and negative controls, respectively. The results shown are of two independent infections per construct (I, II). (c) Qualitative immunofluorescence microscopy analysis for cyclin D1 of post-senescent MEFs immortalised with the indicated constructs and control P3 and P9 MEFs. The scale bar represents 50 μm.