Figure 5. Stable expression of negative regulator of TOR, REDD1, delays the onset of replicative senescence and stable overexpression of eIF4E, accelerates it. (A) Cells expressing REDD1, GFP or eIF4E were assayed by SDS-PAGE western blot (right panel). SDS-PAGE western blot of cells transduced with either REDD1 lentivector (left panel) or eIF4E vector (right panel). (B) Beta-gal staining and passage number of REDD1, eIF4E or control (low passage and high passage) cells. (C) SA-β-gal quantitation of high passage REDD1 cells, eIF4E and low passage control cells.