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. 1998 Apr 6;187(7):1103-11.
doi: 10.1084/jem.187.7.1103.

Human immunodeficiency virus type 1 Vpr is a positive regulator of viral transcription and infectivity in primary human macrophages

R A Subbramanian  1 , A Kessous-Elbaz, R Lodge, J Forget, X J Yao, D Bergeron, E A Cohen
Affiliations

Human immunodeficiency virus type 1 Vpr is a positive regulator of viral transcription and infectivity in primary human macrophages

R A Subbramanian et al. J Exp Med. .

Abstract

It is currently well established that HIV-1 Vpr augments viral replication in primary human macrophages. In its virion-associated form, Vpr has been suggested to aid efficient translocation of the proviral DNA into the cell nucleus. Although Vpr growth-arrests dividing T cells, the relevance of this biological activity in nondividing macrophages is unclear. Here we use Vpr-mutants to demonstrate that the molecular determinants involved in G2-arresting T cells are also involved in increasing viral transcription in macrophages, even though these cells are refractive to the diploid DNA status typical of G2 phase. Our results suggest that the two phenotypes, namely the nuclear localization and the G2-arrest activity of the protein, segregate functionally among the late and early functions of Vpr. The nuclear localization property of Vpr correlates with its ability to effectively target the proviral DNA to the cell nucleus early in the infection, whereas the G2-arrest phenotype correlates with its ability to activate viral transcription after establishment of an infection. These two functions may render Vpr's role essential and not accessory under infection conditions that closely mimic the in vivo situation, that is, primary cells being infected at low viral inputs.

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Figures

Figure 1
Figure 1
Single cycle replication kinetics of viruses expressing the wild-type and mutant Vpr proteins in primary human macrophages. Peripheral blood monocyte–derived macrophages cultured for 7 d were infected with increasing viral inputs ranging from 619 pg to 50 ng (represented in the horizontal axis). Viral production after infection was monitored at regular intervals by measuring p24 levels in the culture supernatants (represented in the vertical axis as p24 ng/ml). The lateral axis represents days after infection spanning the peak of viral replication. Independent experiments performed with different donors and viral stocks consistently showed similar kinetics.
Figure 2
Figure 2
Levels of HIV-1 DNA found in the nuclear compartment among viruses expressing the wild-type and mutant Vpr proteins. (A) Kinetics of proviral DNA detection in the nuclear compartment for wild-type and Vpr negative mutants at a nonsaturating viral input (1.85 ng). HIV Gag sequences found targeted to the nucleus reached a plateau by day 3 and remained constant, indicating that multiple rounds of infection in the presence of the protease inhibitor does not occur in this system. (B) HIV-1 proviral detection in the nuclear compartment at day 14 after infection at various viral inputs for the wild-type, ATG−, R62P, and R80A mutants. Similar levels of cellular DNA were analyzed as indicated by the β2-AR detection. Standards for HIV-Gag detection were measured by diluting uninfected macrophages with a known number of chronically infected ACH-2 cells (48).
Figure 2
Figure 2
Levels of HIV-1 DNA found in the nuclear compartment among viruses expressing the wild-type and mutant Vpr proteins. (A) Kinetics of proviral DNA detection in the nuclear compartment for wild-type and Vpr negative mutants at a nonsaturating viral input (1.85 ng). HIV Gag sequences found targeted to the nucleus reached a plateau by day 3 and remained constant, indicating that multiple rounds of infection in the presence of the protease inhibitor does not occur in this system. (B) HIV-1 proviral detection in the nuclear compartment at day 14 after infection at various viral inputs for the wild-type, ATG−, R62P, and R80A mutants. Similar levels of cellular DNA were analyzed as indicated by the β2-AR detection. Standards for HIV-Gag detection were measured by diluting uninfected macrophages with a known number of chronically infected ACH-2 cells (48).
Figure 3
Figure 3
Productive and silent infection patterns associated with wild-type and Vpr-mutant cultures as assessed by in situ hybridization. Panels depict in situ patterns found in macrophage cultures infected on day 7 after isolation with high viral titers (50 ng) and monitored for RNA expression at 2 wk after infection, when a clear difference in virion production was evident as assessed by supernatant p24 levels (see Fig. 1). Uninfected culture (a), wild-type (b), ATG− (c), R62P (d), and R80A (e).
Figure 3
Figure 3
Productive and silent infection patterns associated with wild-type and Vpr-mutant cultures as assessed by in situ hybridization. Panels depict in situ patterns found in macrophage cultures infected on day 7 after isolation with high viral titers (50 ng) and monitored for RNA expression at 2 wk after infection, when a clear difference in virion production was evident as assessed by supernatant p24 levels (see Fig. 1). Uninfected culture (a), wild-type (b), ATG− (c), R62P (d), and R80A (e).
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References

    1. Arrigo SJ, Chen ISY. Rev is necessary for translation but not cytoplasmic accumulation of HIV-1 vif, vpr, and env/vpu 2 RNAs. Genes Dev. 1991;5:808–819. - PubMed
    1. Garrett ED, Tiley LS, Cullen BR. Rev activates expression of the human immunodeficiency virus type 1 vif and vpr gene products. J Virol. 1991;65:1653–1657. - PMC - PubMed
    1. Tristem M, Marshall C, Karpas A, Petrik J, Hill F. Origin of vpx in lentiviruses. Nature. 1990;347:341–342. - PubMed
    1. Tristem M, Marshall C, Karpas A, Hill F. Evolution of the primate lentiviruses: evidence from vpx and vpr. EMBO (Eur Mol Biol Organ) J. 1992;11:3405–3412. - PMC - PubMed
    1. Balliet JW, Kolson DL, Eiger G, Kim FM, McGann KA, Srinivasan A, Collman R. Distinct effects in primary macrophages and lymphocytes of the human immunodeficiency virus type 1 accessory genes vpr, vpu, and nef: mutational analysis of a primary HIV-1 isolate. Virology. 1994;200:623–631. - PubMed

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