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Viral replication is enhanced by an HIV-1 intersubtype recombination-derived Vpu protein.

De Candia C, Espada C, Duette G, Ghiglione Y, Turk G, Salomón H, Carobene M - Virol. J. (2010)

Bottom Line: Our results showed that BF recombinant Vpu was associated to an increased viral particles production when compared to WT B variant in tetherin-expressing cell lines.The results showed that the replication of the BF Vpu-harboring variant was more efficient in cell cultures than subtype B, reaching a higher frequency in the viral population in a short period of time.This study showed that as a result of intersubtype recombination, a structurally re-organized HIV-1 Vpu has an improved in vitro capacity of enhancing viral replication, and provides evidence of the changes occurring in this protein function that could play an important role in the successful spread of intersubtype recombinant variants.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Reference Center for AIDS, Department of Microbiology, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina.

ABSTRACT

Background: Multiple HIV-1 intersubtype recombinants have been identified in human populations. Previous studies from our lab group have shown that the epidemic in Argentina is characterized by the high prevalence of a circulating recombinant form, CRF12_BF, and many related BF recombinant forms. In these genomic structures a recombination breakpoint frequently involved the vpu coding region. Due to the scarce knowledge of Vpu participation in the virion release process and its impact on pathogenesis and of the functional capacities of intersubtype recombinant Vpu proteins, the aim of this work was to perform a comparative analysis on virion release capacity and relative replication capacity among viral variants harboring either a BF recombinant Vpu or a subtype B Vpu.

Results: Our results showed that BF recombinant Vpu was associated to an increased viral particles production when compared to WT B variant in tetherin-expressing cell lines. This observation was tested in the context of a competition assay between the above mentioned variants. The results showed that the replication of the BF Vpu-harboring variant was more efficient in cell cultures than subtype B, reaching a higher frequency in the viral population in a short period of time.

Conclusion: This study showed that as a result of intersubtype recombination, a structurally re-organized HIV-1 Vpu has an improved in vitro capacity of enhancing viral replication, and provides evidence of the changes occurring in this protein function that could play an important role in the successful spread of intersubtype recombinant variants.

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NL4-3 VpuB and NL4-3 VpuBF viruses were competed against each other by infecting CEM-GFP reporter cells with p24-normalized inocula at 1:1 ratio. Each variant ratio was determined by clonal analysis of viral population present in culture supernatants. Error bars indicate standard errors. Results are representative of two independent experiments.
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Figure 4: NL4-3 VpuB and NL4-3 VpuBF viruses were competed against each other by infecting CEM-GFP reporter cells with p24-normalized inocula at 1:1 ratio. Each variant ratio was determined by clonal analysis of viral population present in culture supernatants. Error bars indicate standard errors. Results are representative of two independent experiments.

Mentions: The relative replication capacity of WT subtypes B and chimeric BF variants was tested in vitro by performing a competitive dual infection. Both variants were used to infect CEM-GFP cell culture, in duplicate, and maintained up to 21 days post-infection (p.i.). Viral population analysis was performed on days 1, 12 and 21 p.i. by cloning and sequencing the vpu coding region, as described in the Material and Methods section. Of note, subtype B sequences were predominant at the beginning (B/BF ratio: 1.52) but its ratio changed over time; the recombinant variant became more frequent (B/BF ratio: 0.99) at the end of the experiment. B/BF variants ratio at each time point is depicted in Figure 4.


Viral replication is enhanced by an HIV-1 intersubtype recombination-derived Vpu protein.

De Candia C, Espada C, Duette G, Ghiglione Y, Turk G, Salomón H, Carobene M - Virol. J. (2010)

NL4-3 VpuB and NL4-3 VpuBF viruses were competed against each other by infecting CEM-GFP reporter cells with p24-normalized inocula at 1:1 ratio. Each variant ratio was determined by clonal analysis of viral population present in culture supernatants. Error bars indicate standard errors. Results are representative of two independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2967538&req=5

Figure 4: NL4-3 VpuB and NL4-3 VpuBF viruses were competed against each other by infecting CEM-GFP reporter cells with p24-normalized inocula at 1:1 ratio. Each variant ratio was determined by clonal analysis of viral population present in culture supernatants. Error bars indicate standard errors. Results are representative of two independent experiments.
Mentions: The relative replication capacity of WT subtypes B and chimeric BF variants was tested in vitro by performing a competitive dual infection. Both variants were used to infect CEM-GFP cell culture, in duplicate, and maintained up to 21 days post-infection (p.i.). Viral population analysis was performed on days 1, 12 and 21 p.i. by cloning and sequencing the vpu coding region, as described in the Material and Methods section. Of note, subtype B sequences were predominant at the beginning (B/BF ratio: 1.52) but its ratio changed over time; the recombinant variant became more frequent (B/BF ratio: 0.99) at the end of the experiment. B/BF variants ratio at each time point is depicted in Figure 4.

Bottom Line: Our results showed that BF recombinant Vpu was associated to an increased viral particles production when compared to WT B variant in tetherin-expressing cell lines.The results showed that the replication of the BF Vpu-harboring variant was more efficient in cell cultures than subtype B, reaching a higher frequency in the viral population in a short period of time.This study showed that as a result of intersubtype recombination, a structurally re-organized HIV-1 Vpu has an improved in vitro capacity of enhancing viral replication, and provides evidence of the changes occurring in this protein function that could play an important role in the successful spread of intersubtype recombinant variants.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Reference Center for AIDS, Department of Microbiology, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina.

ABSTRACT

Background: Multiple HIV-1 intersubtype recombinants have been identified in human populations. Previous studies from our lab group have shown that the epidemic in Argentina is characterized by the high prevalence of a circulating recombinant form, CRF12_BF, and many related BF recombinant forms. In these genomic structures a recombination breakpoint frequently involved the vpu coding region. Due to the scarce knowledge of Vpu participation in the virion release process and its impact on pathogenesis and of the functional capacities of intersubtype recombinant Vpu proteins, the aim of this work was to perform a comparative analysis on virion release capacity and relative replication capacity among viral variants harboring either a BF recombinant Vpu or a subtype B Vpu.

Results: Our results showed that BF recombinant Vpu was associated to an increased viral particles production when compared to WT B variant in tetherin-expressing cell lines. This observation was tested in the context of a competition assay between the above mentioned variants. The results showed that the replication of the BF Vpu-harboring variant was more efficient in cell cultures than subtype B, reaching a higher frequency in the viral population in a short period of time.

Conclusion: This study showed that as a result of intersubtype recombination, a structurally re-organized HIV-1 Vpu has an improved in vitro capacity of enhancing viral replication, and provides evidence of the changes occurring in this protein function that could play an important role in the successful spread of intersubtype recombinant variants.

Show MeSH
Related in: MedlinePlus