Abstract
Abstract: :
Purpose: We determined the stress related gene networks that are controlled by LEDGF in the human LECs. When cells encounter stress conditions, they express various stress–associated proteins. LEDGF is stress inducible transcriptional factor and it appears to be one of the central transcriptional activators to induce stress tolerance in lens epithelial cells (LECs). LEDGF appears to play a vital role in the "cross protection"; a single stress activates multiple stress associated gene networks, which in turn protect cells against many other stress conditions. Methods: Microarray data are generated from four different mRNA preparations. Cells were stably transfected with the GFP–LEDGF construct, empty vector, dsRNAi of LEDGF, or control dsRNAi. Total RNA was extracted and 50 µg of mRNA was submitted to micro array analysis to the UNMC mircoarray core facilities. We selected gene networks with three criteria: 1) up–regulated in LECs over expressing LEDGF, 2) down–regulated in LECs under expressing LEDGF, and 3) the genes that have heat shock element (HSE) and stress related element (STRE) in the promoter sequences since LEDGF binds to HSE and STRE to activate the expression of these genes. Results: We identified several gene networks including antioxidants & antioxidant related enzymes, metal proteins, membrane proteins, detoxification enzymes, heat shock and chaperon proteins, signaling pathway proteins, transcriptional factors, and protein turnover factors, stress response proteins, cell cycle related proteins, cell metabolism, and other proteins. Thus, a single stress activates LEDGF, which activates the wide ranges of stress–associated proteins to cross protect cells from various stresses. Conclusions: We identified the LEDGF dependent stress–associated gene networks, which protect cells from various stresses. We also established that cross protection can be induced by LEDGF by binding to promoter elements to activate many stress related gene networks, which in turn protect cells against many other stress conditions.
Keywords: aging • cell death/apoptosis • gene screening