PMID:12796494

Citation	Maertens, G, Cherepanov, P, Pluymers, W, Busschots, K, De Clercq, E, Debyser, Z and Engelborghs, Y (2003) LEDGF/p75 is essential for nuclear and chromosomal targeting of HIV-1 integrase in human cells. J. Biol. Chem. 278:33528-39
Abstract	We have reported that human immunodeficiency virus type 1 (HIV-1) integrase (IN) forms a specific nuclear complex with human lens epithelium-derived growth factor/transcription co-activator p75 (LEDGF/p75) protein. We now studied the IN-LEDGF/p75 interaction and nuclear import of IN in living cells using fusions of IN and LEDGF/p75 with enhanced green fluorescent protein and far-red fluorescent protein HcRed1. We show that both the N-terminal zinc binding domain and the central core domains of IN are involved in the interaction with LEDGF/p75. Both domains are essential for nuclear localization of IN as well as for the association of IN with condensed chromosomes during mitosis. However, upon overexpression of LEDGF/p75, the core domain fragment of IN was recruited to the nuclei and mitotic chromosomes with a distribution pattern characteristic of the full-length protein, indicating that it harbors the main determinant for interaction with LEDGF/p75. Although the C-terminal domain of IN was dispensable for nuclear/chromosomal localization, a fusion of the C-terminal IN fragment with enhanced green fluorescent protein was found exclusively in the nucleus, with a diffuse nuclear/nucleolar distribution, suggesting that the C-terminal domain may also play a role in the nuclear import of IN. In contrast to LEDGF/p75, its alternative splice variant, p52, did not interact with HIV-1 IN in vitro and in living cells. Finally, RNA interference-mediated knock-down of endogenous LEDGF/p75 expression abolished nuclear/chromosomal localization of IN. We conclude, therefore, that the interaction with LEDGF/p75 accounts for the karyophilic properties and chromosomal targeting of HIV-1 IN.
Links	PubMed Online version:10.1074/jbc.M303594200
Keywords	Active Transport, Cell Nucleus; Alternative Splicing; Base Sequence; Blotting, Western; Cell Nucleus/metabolism; Cells, Cultured; Cytoplasm/metabolism; Fluorescent Antibody Technique, Indirect; HIV Integrase/metabolism; HeLa Cells; Humans; Intercellular Signaling Peptides and Proteins/genetics; Intercellular Signaling Peptides and Proteins/metabolism; Intercellular Signaling Peptides and Proteins/physiology; Microscopy, Confocal; Microscopy, Fluorescence; Mitosis; Models, Genetic; Molecular Sequence Data; Mutation; Plasmids/metabolism; Protein Binding; Protein Structure, Tertiary; RNA, Small Interfering/metabolism; Recombinant Fusion Proteins/metabolism; Transfection; Zinc/chemistry
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
HUMAN:PSIP1	part_of	GO:0005720: nuclear heterochromatin	ECO:0000314: direct assay evidence used in manual assertion		C		Seeded From UniProt	complete
HUMAN:PSIP1	part_of	GO:0005634: nucleus	ECO:0000314: direct assay evidence used in manual assertion		C		Seeded From UniProt	complete

References

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