||Lens Epithelium-derived Growth Factor (LEDGF, also called as p75) has been shown to enhance survival of lens epithelial cells (LECs) against stress. LEDGF is a transcriptional activator. It protects the cells by binding to cis-stress response ((A/T) GGGG (T/A)), and heat shock (HSE; nGAAn) elements in the stress genes and activating their transcription. Originally, it was isolated as a co- activator required for transcriptional activation in human cell-free systems containing RNA Polymerase II and general initiation factors. LEDGF is expressed at all stages of development in a variety of organs and tissues. A second protein product, p52, can be produced from the same gene due to alternative splicing of pre-mRNA. In vitro, p52 was found to be more general and stronger transcriptional co-activator than LEDGF/p75. HIV-1 integrase (IN) forms a specific nuclear complex with p75 but not with p52, suggesting a role for p75's C-terminal region in retroviral integration. Recombinant p75 CTR is isolated from an E.coli strain that carries the C-terminal coding sequence of the human LEDGF/p75(amino acid 322-530) under the control of a T7 promoter. p75 has been applied in in vitro transcription assays, splicing assays, DNA and protein-protein interaction assays. The purified recombinant protein is greater than 95% homogeneous and contains no detectable protease, DNase, and RNase activity.