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The human antiviral factor TRIM11 is under the regulation of HIV-1 Vpr.

Yuan T, Yao W, Huang F, Sun B, Yang R - PLoS ONE (2014)

Bottom Line: In this study, we demonstrated that TRIM11 mainly suppressed the early steps of HIV-1 transduction, resulting in decreased reverse transcripts.Additionally, we found that TRIM11 could inhibit HIV-1 long terminal repeat (LTR) activity, which may be related to its inhibitory effects on NF-κB.These results suggest that the antiviral factor TRIM11 is indirectly regulated by HIV-1 Vpr through unknown mechanisms and that the concentration of Vpr is essential to these processes.

View Article: PubMed Central - PubMed

Affiliation: Research Group of HIV Molecular Epidemiology and Virology, Center for Emerging Infectious Diseases, The State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, The People's Republic of China.

ABSTRACT
TRIM11 has been reported to be able to restrict HIV-1 replication, but the detailed aspects of the interfering mechanisms remain unclear. In this study, we demonstrated that TRIM11 mainly suppressed the early steps of HIV-1 transduction, resulting in decreased reverse transcripts. Additionally, we found that TRIM11 could inhibit HIV-1 long terminal repeat (LTR) activity, which may be related to its inhibitory effects on NF-κB. Deletion mutant experiments showed that the RING domain of TRIM11 was indispensable in inhibiting the early steps of HIV-1 transduction but was dispensable in decreasing NF-κB and LTR activities. Moreover, we found that low levels of Vpr decreased TRIM11 protein levels, while high levels increased them, and these regulations were independent of the VprBP-associated proteasome machinery. These results suggest that the antiviral factor TRIM11 is indirectly regulated by HIV-1 Vpr through unknown mechanisms and that the concentration of Vpr is essential to these processes. Thus, our work confirms TRIM11 as a host cellular factor that interferes with the early steps of HIV-1 replication and provides a connection between viral protein and host antiviral factors.

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Effects of Vpr on TRIM11 protein levels.A. HEK293 cells were cotransfected with TRIM11 expression plasmids and increasing amounts of Vpr expressing plasmids for 24 h and cell lysates were immunoblotted with the indicated antibodies. B, D. HEK293 cells that were transfected with TRIM11-expressing plasmids (B) for 24 h or not (D) were inoculated with increasing amounts of HIV-1 Vpr− or HIV Vpr+ virus. Cell lysates were immunoblotted with the indicated antibodies at 12 hpi (B) or 24 hpi (D). C, E. HEK293 cells that were transfected with TRIM11-expressing plasmids (C) for 24 h or not (E) were inoculated with 20 ng/ml (p24gag) of HIV-1 Vpr− and HIV-1 Vpr+ viruses for different periods of time. Cell lysates were immunoblotted with the indicated antibodies. The numbers under each line display the relative ratios between the Myc or TRIM11 signals and actin signals. Representative results from three separate experiments are shown.
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pone-0104269-g005: Effects of Vpr on TRIM11 protein levels.A. HEK293 cells were cotransfected with TRIM11 expression plasmids and increasing amounts of Vpr expressing plasmids for 24 h and cell lysates were immunoblotted with the indicated antibodies. B, D. HEK293 cells that were transfected with TRIM11-expressing plasmids (B) for 24 h or not (D) were inoculated with increasing amounts of HIV-1 Vpr− or HIV Vpr+ virus. Cell lysates were immunoblotted with the indicated antibodies at 12 hpi (B) or 24 hpi (D). C, E. HEK293 cells that were transfected with TRIM11-expressing plasmids (C) for 24 h or not (E) were inoculated with 20 ng/ml (p24gag) of HIV-1 Vpr− and HIV-1 Vpr+ viruses for different periods of time. Cell lysates were immunoblotted with the indicated antibodies. The numbers under each line display the relative ratios between the Myc or TRIM11 signals and actin signals. Representative results from three separate experiments are shown.

Mentions: To determine whether any HIV-1 protein plays a role in antagonizing TRIM11 activity, we examined the effects of all HIV-1 proteins on TRIM11. The results indicated that among the six expressed proteins (Tat, Nef, Pol, Vif, Rev and Vpr), only Tat and Vpr could decrease TRIM11 protein levels (Figure S2A). To confirm these results, we cotransfected HEK293 cells with increasing amounts of Vpr or Tat and a fixed amount of the TRIM11-expression vector. Interestingly, the transfection of 200 ng of the Vpr-expression vector severely down-regulated TRIM11, while its protein levels were recovered as the concentration of Vpr increased (Figure 5A). Tat only affected TRIM11 protein levels weakly in a dose-dependent manner (Figure S2B).


The human antiviral factor TRIM11 is under the regulation of HIV-1 Vpr.

Yuan T, Yao W, Huang F, Sun B, Yang R - PLoS ONE (2014)

Effects of Vpr on TRIM11 protein levels.A. HEK293 cells were cotransfected with TRIM11 expression plasmids and increasing amounts of Vpr expressing plasmids for 24 h and cell lysates were immunoblotted with the indicated antibodies. B, D. HEK293 cells that were transfected with TRIM11-expressing plasmids (B) for 24 h or not (D) were inoculated with increasing amounts of HIV-1 Vpr− or HIV Vpr+ virus. Cell lysates were immunoblotted with the indicated antibodies at 12 hpi (B) or 24 hpi (D). C, E. HEK293 cells that were transfected with TRIM11-expressing plasmids (C) for 24 h or not (E) were inoculated with 20 ng/ml (p24gag) of HIV-1 Vpr− and HIV-1 Vpr+ viruses for different periods of time. Cell lysates were immunoblotted with the indicated antibodies. The numbers under each line display the relative ratios between the Myc or TRIM11 signals and actin signals. Representative results from three separate experiments are shown.
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Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4126725&req=5

pone-0104269-g005: Effects of Vpr on TRIM11 protein levels.A. HEK293 cells were cotransfected with TRIM11 expression plasmids and increasing amounts of Vpr expressing plasmids for 24 h and cell lysates were immunoblotted with the indicated antibodies. B, D. HEK293 cells that were transfected with TRIM11-expressing plasmids (B) for 24 h or not (D) were inoculated with increasing amounts of HIV-1 Vpr− or HIV Vpr+ virus. Cell lysates were immunoblotted with the indicated antibodies at 12 hpi (B) or 24 hpi (D). C, E. HEK293 cells that were transfected with TRIM11-expressing plasmids (C) for 24 h or not (E) were inoculated with 20 ng/ml (p24gag) of HIV-1 Vpr− and HIV-1 Vpr+ viruses for different periods of time. Cell lysates were immunoblotted with the indicated antibodies. The numbers under each line display the relative ratios between the Myc or TRIM11 signals and actin signals. Representative results from three separate experiments are shown.
Mentions: To determine whether any HIV-1 protein plays a role in antagonizing TRIM11 activity, we examined the effects of all HIV-1 proteins on TRIM11. The results indicated that among the six expressed proteins (Tat, Nef, Pol, Vif, Rev and Vpr), only Tat and Vpr could decrease TRIM11 protein levels (Figure S2A). To confirm these results, we cotransfected HEK293 cells with increasing amounts of Vpr or Tat and a fixed amount of the TRIM11-expression vector. Interestingly, the transfection of 200 ng of the Vpr-expression vector severely down-regulated TRIM11, while its protein levels were recovered as the concentration of Vpr increased (Figure 5A). Tat only affected TRIM11 protein levels weakly in a dose-dependent manner (Figure S2B).

Bottom Line: In this study, we demonstrated that TRIM11 mainly suppressed the early steps of HIV-1 transduction, resulting in decreased reverse transcripts.Additionally, we found that TRIM11 could inhibit HIV-1 long terminal repeat (LTR) activity, which may be related to its inhibitory effects on NF-κB.These results suggest that the antiviral factor TRIM11 is indirectly regulated by HIV-1 Vpr through unknown mechanisms and that the concentration of Vpr is essential to these processes.

View Article: PubMed Central - PubMed

Affiliation: Research Group of HIV Molecular Epidemiology and Virology, Center for Emerging Infectious Diseases, The State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, The People's Republic of China.

ABSTRACT
TRIM11 has been reported to be able to restrict HIV-1 replication, but the detailed aspects of the interfering mechanisms remain unclear. In this study, we demonstrated that TRIM11 mainly suppressed the early steps of HIV-1 transduction, resulting in decreased reverse transcripts. Additionally, we found that TRIM11 could inhibit HIV-1 long terminal repeat (LTR) activity, which may be related to its inhibitory effects on NF-κB. Deletion mutant experiments showed that the RING domain of TRIM11 was indispensable in inhibiting the early steps of HIV-1 transduction but was dispensable in decreasing NF-κB and LTR activities. Moreover, we found that low levels of Vpr decreased TRIM11 protein levels, while high levels increased them, and these regulations were independent of the VprBP-associated proteasome machinery. These results suggest that the antiviral factor TRIM11 is indirectly regulated by HIV-1 Vpr through unknown mechanisms and that the concentration of Vpr is essential to these processes. Thus, our work confirms TRIM11 as a host cellular factor that interferes with the early steps of HIV-1 replication and provides a connection between viral protein and host antiviral factors.

Show MeSH
Related in: MedlinePlus