Lens epithelium-derived growth factor (LEDGF) fusion proteins can direct HIV-1 DNA integration to novel sites in the host genome. The C terminus of LEDGF contains an integrase binding domain (IBD), and the N terminus binds chromatin. LEDGF normally directs integrations to the bodies of expressed genes. Replacing the N terminus of LEDGF with chromatin binding domains (CBDs) from other proteins changes the specificity of HIV-1 DNA integration. We chose two well-characterized CBDs: the plant homeodomain (PHD) finger from ING2 and the chromodomain from heterochromatin binding protein 1alpha (HP1alpha). The ING2 PHD finger binds H3K4me3, a histone mark that is associated with the transcriptional start sites of expressed genes. The HP1alpha chromodomain binds H3K9me2,3, histone marks that are widely distributed throughout the genome. A fusion protein in which the ING2 PHD finger was linked to the LEDGF IBD directed integrations near the start sites of expressed genes. A similar fusion protein in which the HP1alpha chromodomain was linked to the LEDGF IBD directed integrations to sites that differed from both the PHD finger fusion-directed and LEDGF-directed integration sites. The ability to redirect HIV-1 DNA integration may help solve the problems associated with the activation of oncogenes when retroviruses are used in gene therapy.
Proc Natl Acad Sci U S A
3135 - 3140
Animals, Binding Sites, Cell Line, Chromatin, Computational Biology, DNA, Viral, Flow Cytometry, Gene Expression Profiling, Genetic Therapy, HIV Integrase, HIV-1, Homeodomain Proteins, Intercellular Signaling Peptides and Proteins, Mice, Mice, Knockout, Protein Structure, Tertiary, Sequence Analysis, DNA, Tumor Suppressor Proteins, Virus Integration