Integration of the human immunodeficiency virus type 1 (HIV-1) cDNA into the human genome is catalyzed by the viral integrase protein that requires the lens epithelium-derived growth factor (LEDGF), a cellular transcriptional coactivator. In the presence of LEDGF, integrase forms a stable complex in vitro and importantly becomes soluble by contrast with integrase alone which aggregates and precipitates. Using cryo-electron microscopy (EM) and single-particle reconstruction, we obtained three-dimensional structures of the wild type full length integrase-LEDGF complex with and without DNA . The stoichiometry of the complex was found to be (integrase)4-(LEDGF)2 by mass spectrometry analysis and existing atomic structures were unambiguous positioned in the EM map. In vitro functional assays reveal that LEDGF increases integrase activity likely in maintaining a stable and functional integrase structure. DNA-Protein cross-linking experiments show specific interaction between viral DNA and the C-terminal domain of integrase. Upon DNA binding, IN undergoes large conformational changes. Cryo-EM structure underlines the path of viral and target DNA and a model for DNA integration in human DNA is proposed (see fig. 1, overleaf).
IGBMC, UDS, U596 Inserm, UMR7104 CNRS
Laboratoire de Biotechnologie et Pharmacologie Génétique Appliquée, CNRS, UMR8113, ENS-Cachan
Belozersky Institute of Physico-Chemical Biology, Moscow State University
CovalX, Technoparkstrasse, 1
Institut Cochin, Université Paris Descartes, CNRS (UMR8104), Inserm, U567
CellVir SAS, Evry, France; Hybrigenics SA
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