title: Interaction of human immunodeficiency virus type 1 integrase with cellular nuclear import receptor importin 7 and its impact on viral replication.
abstract: Similar to all other viruses, human immunodeficiency virus type 1 (HIV-1) depends heavily on cellular factors for its successful replication. In this study we have investigated the interaction of HIV-1 integrase (IN) with several host nuclear import factors using co-immunoprecipitation assays. Our results indicate that IN interacts specifically with host importin 7 (Imp7) in vivo, but does not interact with importin 8 (Imp8) or importin alpha (Rch1). In contrast, another HIV-1 karyophilic protein MAp17, which is capable of binding Rch1, fails to interact with Imp7, suggesting that IN and Map17 may interact with different cellular pathways during HIV-1 replication. Genetic analysis revealed that the C-terminal domain of IN is the region responsible for interaction between IN with Imp7, and an IN mutant (K240A,K244A/R263A,K264A) disrupted the Imp7 binding ability of the protein, indicating that both regions ((235)WKGPAKLLWKG and (262)RRKAK) within the C-terminal domain of IN are required for efficient IN/Imp7 interaction. Using a vesicular stomatitis virus G glycoprotein pseudotyped HIV single-cycle replication system, we showed that the IN/Imp7 interaction-deficient mutant was unable to mediate viral replication and displayed impairment at both viral reverse transcription and nuclear import steps. Moreover, transient knockdown of Imp7 in both HIV-1 producing and target cells resulted in a 2.5-3.5-fold inhibition of HIV infection. Altogether, our results indicate that HIV-1 IN specifically interacts with Imp7, and this viral/cellular protein interaction contributes to efficient HIV-1 infection.
authors.affiliation: Laboratory of Molecular Human Retrovirology, Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, R3E 0W3.
authors.forename: Zhujun
authors.initials: Z
authors.lastname: Ao
authors.forename: Guanyou
authors.initials: G
authors.lastname: Huang
authors.forename: Han
authors.initials: H
authors.lastname: Yao
authors.forename: Zaikun
authors.initials: Z
authors.lastname: Xu
authors.forename: Meaghan
authors.initials: M
authors.lastname: Labine
authors.forename: Alan W
authors.initials: AW
authors.lastname: Cochrane
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Yao
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000235:genetics; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D015658:HIV Infections / Q000235:genetics / Q000378:metabolism*; D019427:HIV Integrase / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D028884:Karyopherins / Q000235:genetics / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins; D009154:Mutation; D011485:Protein Binding / Q000235:genetics; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication / Q000235:genetics; D028901:alpha Karyopherins / Q000235:genetics / Q000378:metabolism
chemical_list: C028391:G protein, vesicular stomatitis virus; C466996:IPO7 protein, human; D028884:Karyopherins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C509768:PDZK1IP1 protein, human; D018160:Receptors, Cytoplasmic and Nuclear; D014759:Viral Envelope Proteins; D028901:alpha Karyopherins; C087978:karyopherin alpha 2; D019427:HIV Integrase