LEDGF binds to heat shock and stress-related element to activate the expression of stress-related genes

We have investigated the mechanism by which LEDGF protects cells against en vironmental stress. Our earlier report showed that a low level of LEDGF was present in the nucleus of most cell types and significant elevation of LED GE level was induced by heat and oxidative stress. The cells overexpressing LEDGF-activated expression of heat shock proteins and enhanced survival of many cell types. Here we show that LEDGF binds to heat shock element (HSE) and stress-related regulatory element (STRE) to activate the expression of stress-related genes (Hsp27 and alpha beta -crystallin). Apparently, HSE a nd STRE are present in promoters of many stress-related genes. Elevation of many stress-related proteins (STRPs) induced by LEDGE may protect cells ag ainst environmental stress. In yeast, it has been demonstrated that a singl e stress can activate the expression of multiple STRPs. This is known as "c ross-protection," and now similar mechanism has been found in mammalian cel ls and LEDGF plays a vital role in it. (C) 2001 Academic Press.