Figure 2

Growth properties of Gtf2i ^Δex2 mutant MEFs. A. Spontaneous immortalization. Eleven independent MEF cultures showing early immortalization in Gtf2i ^Δex2/Δex2 and later in Gtf2i ^+/Δex2 cells. B. Saturation rate. 10⁶ cells plated by triplicate and counted every three days until they reached the maximum score. A poorer saturation rate was observed in Gtf2i ^+/Δex2 cells. C. Proliferation of immortal MEFs. Three independent experiments were performed with all cell types and each time point was done by triplicate. The fastest proliferation was observed in Gtf2i ^Δex2/Δex2 while Gtf2i ^+/Δex2 cells performed the worst. D. Re-entry into S-phase after serum deprivation. The percentage of cells in S-phase was measured at the indicated times after serum stimulation. Again Gtf2i ^+/Δex2 MEFs showed the lowest rate of S-phase re-entry. Gtf2i ^+/+, open rhombus; Gtf2i ^+/Δex2 grey squares; Gtf2i ^Δex2/Δex2 black triangles. All values are expressed as mean ± s.d.