LEDGF promotes survival of many cell types against a wide range of environmental stresses, and cells responding to those stresses expressed higher levels of heat shock proteins (Hsps). LEDGF/p75 is a weak coactivator of general transcription. We speculated that a stress signal may activate expression of the LEDGF gene, resulting in elevated levels of LEDGF which may activate expression of stress-related proteins to protect cells from stresses. Lens epithelial cells (LECs) and cos7 cells were cultured under heat- or oxidative-stress, After cells mere cultured for defined time, we quantified LEDGF mRNA and LEDGF protein with RT-PCR, Northern blot, and protein blot analysis, Our results showed that higher levels of LEDGF were found in both cell types under heat- and oxdative-stress than that in cells cultured at nonstress condition. Thus, one of the primary events in the stress-related protective events is the activation of LEDGF, a regulatory protein,