HIV-1 Integrase Forms Stable Tetramers and Associates with LEDGF/p75 Protein in Human Cells

Peter Cherepanov, Goedele Maertens, Paul Proost, Bart Devreese, Jozef Van Beeumen, Yves Engelborghs, Erik De Clercq, Zeger Debyser
2002 Journal of Biological Chemistry  
We studied human immunodeficiency virus, type 1 (HIV-1) integrase (IN) complexes derived from nuclei of human cells stably expressing the viral protein from a synthetic gene. We show that in the nuclear extracts IN exists as part of a large distinct complex with an apparent Stokes radius of 61 Å, which dissociates upon dilution yielding a core molecule of 41 Å. We isolated the IN complexes from cells expressing FLAG-tagged IN and demonstrated that the 41 Å core is a tetramer of IN, whereas 61 Å
more » ... molecules are composed of IN tetramers associated with a cellular protein with an apparent molecular mass of 76 kDa. This novel integrase interacting protein was found to be identical to lens epitheliumderived growth factor (LEDGF/p75), a protein implicated in regulation of gene expression and cellular stress response. HIV-1 IN and LEDGF co-localized in the nuclei of human cells stably expressing IN. Furthermore, recombinant LEDGF robustly enhanced strand transfer activity of HIV-1 IN in vitro. Our findings indicate that the minimal IN molecule in human cells is a homotetramer, suggesting that at least an octamer of IN is required to accomplish coordinated integration of both retroviral long terminal repeats and that LEDGF is a cellular factor involved in this process.
doi:10.1074/jbc.m209278200 pmid:12407101 fatcat:h26kmbt35vgutaqw5pgm3swbxi