Result: Notably, other Vpr mutants, including Q65R, R77Q and R80A, showed similar activity with Vpr-Wt (Additional file 1: Figure S1c
Figure: For this experiment, we newly established cell lines (HT1080vRxt-Vpr), in which expression of Vpr-Wt (lanes 3 and 4), Vpr-Q65R (lanes 5 and 6), Vpr-R77Q (lanes 7 and 8), Vpr-R80A (lanes 9 and 10) and Vpr-Ct4RA (lanes 11 and 12) can be controlled by the tetracycline promoter, and ubiquitination of H2B on K120 was examined after Dox treatment (5 mug/ml, 2 days).
SLX4-SLX1 Protein-independent Down-regulation of MUS81-EME1 Protein by HIV-1 Viral Protein R (Vpr).
PMID: 27354282
2016
The Journal of biological chemistry
Abstract: Furthermore, a C-terminally truncated Vpr mutant and point mutants R80A and Q65R, all of which lack G2 arrest activity, are able to down-regulate MUS81-EME1, suggesting that Vpr-induced G2 arrest is not correlated with MUS81-EME1 down-regulation.
R77Q and Q3R HIV1-VPR mutations in an otherwise asymptomatic 5-year-old child with repeated ear infections.
Figure: Mutation of Arg-80 with Ala does not influence the secondary structure of Vpr75-90.
Figure: SPR sensorgrams for synthetic Vpr75-90, the mutants Vpr75-90 (R76Q, V83I, T84I), Vpr75-90 (R76Q, V83I, R80A, T84I), Vpr75-90 (R80A) and the shorter peptides Vpr69-78, Vpr75-84, Vpr81-90 and Vpr87-96 were analyzed for binding to immobilized recombinant CypA.
PP2A1 binding, cell transducing and apoptotic properties of Vpr(77-92): a new functional domain of HIV-1 Vpr proteins.
Abstract: In addition the double R77A and R80A mutation known to inactivate the mitochondriotoxic Vpr(71-82) domain, has no effect on the biological properties of the Vpr(77-92) domain.
Discussion: In contrast the double substitution, R77A and R80A, allowed the binding to PP2A1 holoenzyme.
Discussion: Interestingly the R80A substitution renders also Vpr inactive for cell cycle arrest but the R77A and R80A substitutions that affect direct binding of Vpr 71-82 to ANT and inactivate the michondriontoxic domain activity did not prevented apoptosis induction.
HIV-1 Vpr activates the G2 checkpoint through manipulation of the ubiquitin proteasome system.
Result: Vpr(Q65R, R80A) did not behave as a dominant-negative protein (Figure 4; see also Additional file 3).
Result: Vpr(Q65R, R80A) was, as expected, unable to bind DCAF (data not shown), or to induce G2 arrest (Figure 4).
Result: The inability
Result: Thus, we constructed the double mutant, Vpr(Q65R, R80A).
Result: To test the previous idea, we co-infected cells with a constant amount of pHR-Vpr vector (MOI = 1.0) and decreasing amounts of Vpr(R80A) (MOIs of 1, 0.5 and 0.25), and then assessed the cell cyle profile in these cultures (Figure 4).
Localization of HIV-1 Vpr to the nuclear envelope: impact on Vpr functions and virus replication in macrophages.
Abstract: However, this localization is not sufficient, since mutations within the C-terminal basic region of Vpr (Vpr-R80A and Vpr-R90K), disrupted the G2-arrest and apoptotic activities without altering NE localization.
Method: Most of the yeast and mammalian expression plasmids used in this study have been described previously, except plasmids for expression of the Vpr mutants with L23F and K27M substitutions; the Vpr mutant with the R80A substitution was kindly provided by E.
Result: As controls, the Vpr-R80A and -R90K variants, whi
Effect of R77Q, R77A and R80A changes in Vpr on HIV-1 replication and CD4 T cell depletion in human lymphoid tissue ex vivo.
Abstract: BACKGROUND: It has been suggested that mutations of R77A and R80A in the HIV-1 viral protein R (Vpr) impair its proapoptotic activity and that a naturally occurring R77Q variation is associated with non-progressive HIV-1 infection.
Abstract: Mutation of R77Q and R80A reduced apoptosis of HIV-1-infected cells in ex vivo-infected HLT independently of the viral coreceptor tropism.
Abstract: RATIONALE: To assess the effect of Vpr R77Q, R77A and R80A mutations on the efficiency of CCR5(R5)- and CXCR4(X4)-tropic HIV-1 replication and cytopathicity in human lymphoid tissue (HLT).
HIV-1 Vpr-induced apoptosis is cell cycle dependent and requires Bax but not ANT.
Result: As a control, we used isogenic vectors expressing a mutant form of Vpr, pHR-VPR(R80A), wherein Vpr(R80A) is defective in induction of G2 arrest and apoptosis.
Result: Because the fusion with carboxyl-terminal GFP turns Vpr(R80A), a nonproaptotic protein, into an apoptotic one, it appears that the induction of apoptosis by Vpr-GFP represents a gain-of-function phenotype and is not representative of the biology of wild-type Vpr.
Result: Both Vpr-GFP and Vpr(R80A)-GFP were able to induce apoptosis.
Result: Since Vpr
Vpr protein of human immunodeficiency virus type 1 binds to 14-3-3 proteins and facilitates complex formation with Cdc25C: implications for cell cycle arrest.
HIV mutation literature information.
PMID: 
2018
Retrovirology
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