Two nuclear localization signals in the HIV-1 matrix protein regulate nuclear import of the HIV-1 pre-integration complex.
Replication of HIV-1 in non-dividing and slowly proliferating cell populations depends on active import of the viral pre-integration complex (PIC) into the cell nucleus. While it is commonly accepted that this process is mediated by an interaction between the HIV-1 PIC and the cellular nuclear import machinery, controversial results have been reported concerning the mechanisms of this interaction. Here, we demonstrate that a recently identified nuclear localization signal within the HIV-1 matrix protein (MA), MA NLS-2, together with previously described MA NLS-1, mediates nuclear import of the HIV-1 PIC. Inactivation of both MA NLSs precluded nuclear translocation of MA and rendered the virus defective in nuclear import and replication in non-dividing macrophage cultures, even when functional Vpr and integrase (IN), two more viral proteins implicated in HIV-1 nuclear import, were present. Taken together, these results indicate that Vpr does not function as an independent nuclear import factor and demonstrate that HIV-1 MA, by virtue of its two nuclear localization signals, regulates HIV-1 nuclear import.
Haffar
O K
OK
Cytokine Networks Inc., Seattle, WA, 98119, USA.
Popov
S
S
Dubrovsky
L
L
Agostini
I
I
Tang
H
H
Pushkarsky
T
T
Nadler
S G
SG
Bukrinsky
M
M
D000595:Amino Acid Sequence; D001692:Biological Transport; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D004279:DNA, Viral / Q000032:analysis / Q000235:genetics; D015683:Gene Products, gag / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016336:Gene Products, vpr / Q000235:genetics / Q000378:metabolism; D015488:HIV Antigens / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D019427:HIV Integrase / Q000235:genetics / Q000378:metabolism; D054303:HIV Reverse Transcriptase / Q000378:metabolism; D015497:HIV-1 / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000821:virology; D009154:Mutation / Q000235:genetics; D019913:Nuclear Localization Signals / Q000235:genetics / Q000502:physiology*; D009687:Nuclear Proteins / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D014764:Viral Proteins; D016662:Virus Integration; D014779:Virus Replication; D028901:alpha Karyopherins; D054301:gag Gene Products, Human Immunodeficiency Virus; D054325:vpr Gene Products, Human Immunodeficiency Virus
D004279:DNA, Viral; D015683:Gene Products, gag; D016336:Gene Products, vpr; D015488:HIV Antigens; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins; D014764:Viral Proteins; D028901:alpha Karyopherins; D054301:gag Gene Products, Human Immunodeficiency Virus; C054858:p17 protein, Human Immunodeficiency Virus Type 1; D054325:vpr Gene Products, Human Immunodeficiency Virus; D019427:HIV Integrase; D054303:HIV Reverse Transcriptase