scholarly journals Human Immunodeficiency Virus Type 1 Vif Inhibits Packaging and Antiviral Activity of a Degradation-Resistant APOBEC3G Variant

2007 ◽  
Vol 81 (15) ◽  
pp. 8236-8246 ◽  
Author(s):  
Sandrine Opi ◽  
Sandra Kao ◽  
Ritu Goila-Gaur ◽  
Mohammad A. Khan ◽  
Eri Miyagi ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cytidine Deaminase ◽  
Natural Tendency ◽  
Immunodeficiency Virus ◽  
Dependent Processes ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) Vif counteracts the antiviral activity of the human cytidine deaminase APOBEC3G (APO3G) by inhibiting its incorporation into virions. This has been attributed to the Vif-induced degradation of APO3G by cytoplasmic proteasomes. We recently demonstrated that although APO3G has a natural tendency to form RNA-dependent homo-multimers, multimerization was not essential for encapsidation into HIV-1 virions or antiviral activity. We now demonstrate that a multimerization-defective APO3G variant (APO3G C97A) is able to assemble into RNase-sensitive high-molecular-mass (HMM) complexes, suggesting that homo-multimerization of APO3G and assembly into HMM complexes are unrelated RNA-dependent processes. Interestingly, APO3G C97A was highly resistant to Vif-induced degradation even though the two proteins were found to interact in coimmunoprecipitation experiments and exhibited partial colocalization in transfected HeLa cells. Surprisingly, encapsidation and antiviral activity of APO3G C97A were both inhibited by Vif despite resistance to degradation. These results demonstrate that targeting of APO3G to proteasome degradation and interference with viral encapsidation are distinct functional properties of Vif.

scholarly journals Human Immunodeficiency Virus Type 1 Replication and Regulation of APOBEC3G by Peptidyl Prolyl Isomerase Pin1

2008 ◽  
Vol 82 (20) ◽  
pp. 9928-9936 ◽  
Author(s):  
Koichi Watashi ◽  
Mohammad Khan ◽  
Venkat R. K. Yedavalli ◽  
Man Lung Yeung ◽  
Klaus Strebel ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cytidine Deaminase ◽  
Prolyl Isomerase ◽  
Interacting Protein ◽  
New Findings ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT APOBEC3G (A3G) is a cytidine deaminase that restricts human immunodeficiency virus type 1 (HIV-1) replication. HIV-1 synthesizes a viral infectivity factor (Vif) to counter A3G restriction. Currently, it is poorly understood how A3G expression/activity is regulated by cellular factors. Here, we show that the prolyl isomerase Pin1 protein modulates A3G expression. Pin1 was found to be an A3G-interacting protein that reduces A3G expression and its incorporation into HIV-1 virion, thereby limiting A3G-mediated restriction of HIV-1. Intriguingly, HIV-1 infection modulates the phosphorylation state of Pin1, enhancing its ability to moderate A3G activity. These new findings suggest a potential Vif-independent way for HIV-1 to moderate the cellular action of A3G.

scholarly journals The Thiocarboxanilide Nonnucleoside Inhibitor UC781 Restores Antiviral Activity of 3′-Azido-3′-Deoxythymidine (AZT) against AZT-Resistant Human Immunodeficiency Virus Type 1

1999 ◽  
Vol 43 (2) ◽  
pp. 259-263 ◽  
Author(s):  
Gadi Borkow ◽  
Dominique Arion ◽  
Mark A. Wainberg ◽  
Michael A. Parniak
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Wild Type Virus ◽  
Wild Type ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT N-[4-Chloro-3-(3-methyl-2-butenyloxy)phenyl]-2-methyl-3-furancarbothioamide (UC781) is an exceptionally potent nonnucleoside inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase. We found that a 1:1 molar combination of UC781 and 3′-azido-3′-deoxythymidine (AZT) showed high-level synergy in inhibiting the replication of AZT-resistant virus, implying that UC781 can restore antiviral activity to AZT against AZT-resistant HIV-1. Neither the nevirapine plus AZT nor the 2′,5′-bis-O-(t-butyldimethylsilyl)-3′-spiro-5"-(4"-amino-1",2"-oxathiole-2",2"-dioxide plus AZT combinations had this effect. Studies with purified HIV-1 reverse transcriptase (from a wild type and an AZT-resistant mutant) showed that UC781 was a potent inhibitor of the pyrophosphorolytic cleavage of nucleotides from the 3′ end of the DNA polymerization primer, a process that we have proposed to be critical for the phenotypic expression of AZT resistance. Combinations of UC781 plus AZT did not act in synergy to inhibit the replication of either wild-type virus or UC781-resistant HIV-1. Importantly, the time to the development of viral resistance to combinations of UC781 plus AZT is significantly delayed compared to the time to the development of resistance to either drug alone.

scholarly journals Viral RNA Is Required for the Association of APOBEC3G with Human Immunodeficiency Virus Type 1 Nucleoprotein Complexes

2005 ◽  
Vol 79 (9) ◽  
pp. 5870-5874 ◽  
Author(s):  
Mohammad A. Khan ◽  
Sandra Kao ◽  
Eri Miyagi ◽  
Hiroaki Takeuchi ◽  
Ritu Goila-Gaur ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cytidine Deaminase ◽  
Viral Rna ◽  
Target Sequence ◽  
Immunodeficiency Virus ◽  
Nucleoprotein Complexes ◽  
Hiv 1

ABSTRACT APOBEC3G (APO3G) is a host cytidine deaminase that is incorporated into human immunodeficiency virus type 1 (HIV-1) particles. We report here that viral RNA promotes stable association of APO3G with HIV-1 nucleoprotein complexes (NPC). A target sequence located within the 5′-untranslated region of the HIV-1 RNA was identified to be necessary and sufficient for efficient APO3G packaging. Fine mapping revealed a sequence normally involved in viral genomic RNA dimerization and Gag binding to be important for APO3G packaging and association with viral NPC. Our data suggest that packaging of APO3G into HIV-1 NPC is enhanced by viral RNA.

Antiviral activity of Hawaiian medicinal plants against human immunodeficiency Virus Type-1 (HIV-1)

Phytomedicine ◽  
1996 ◽  
Vol 2 (3) ◽  
pp. 259-264 ◽  
Author(s):  
Christopher P. Locher ◽  
Myriam Witvrouw ◽  
Marie-Pierre De Béthune ◽  
Mark T. Burch ◽  
Howard F. Mower ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Medicinal Plants ◽  
Antiviral Activity ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Immunodeficiency Virus ◽  
Hiv 1

scholarly journals Differential Sensitivity of “Old” versus “New” APOBEC3G to Human Immunodeficiency Virus Type 1 Vif

2008 ◽  
Vol 83 (2) ◽  
pp. 1156-1160 ◽  
Author(s):  
Ritu Goila-Gaur ◽  
Mohammad A. Khan ◽  
Eri Miyagi ◽  
Klaus Strebel
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Hela Cells ◽  
Relative Sensitivity ◽  
Differential Sensitivity ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT HIV-1 Vif counteracts the antiviral activity of APOBEC3G by inhibiting its encapsidation into virions. Here, we compared the relative sensitivity to Vif of APOBEC3G in stable HeLa cells containing APOBEC3G (HeLa-A3G cells) versus that of newly synthesized APOBEC3G. We observed that newly synthesized APOBEC3G was more sensitive to degradation than preexisting APOBEC3G. Nevertheless, preexisting and transiently expressed APOBEC3G were packaged with similar efficiencies into vif-deficient human immunodeficiency virus type 1 (HIV-1) virions, and Vif inhibited the encapsidation of both forms of APOBEC3G into HIV particles equally well. Our results suggest that HIV-1 Vif preferentially induces degradation of newly synthesized APOBEC3G but indiscriminately inhibits encapsidation of “old” and “new” APOBEC3G.

scholarly journals Enzymatically Active APOBEC3G Is Required for Efficient Inhibition of Human Immunodeficiency Virus Type 1

2007 ◽  
Vol 81 (24) ◽  
pp. 13346-13353 ◽  
Author(s):  
Eri Miyagi ◽  
Sandrine Opi ◽  
Hiroaki Takeuchi ◽  
Mohammad Khan ◽  
Ritu Goila-Gaur ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Genome ◽  
Cytidine Deaminase ◽  
Immunodeficiency Virus ◽  
Catalytically Active ◽  
Antiviral Activities

ABSTRACT APOBEC3G (APO3G) is a cellular cytidine deaminase with potent antiviral activity. Initial studies of the function of APO3G demonstrated extensive mutation of the viral genome, suggesting a model in which APO3G's antiviral activity is due to hypermutation of the viral genome. Recent studies, however, found that deaminase-defective APO3G mutants transiently expressed in virus-producing cells exhibited significant antiviral activity, suggesting that the antiviral activity of APO3G could be dissociated from its deaminase activity. To directly compare the antiviral activities of wild-type (wt) and deaminase-defective APO3G, we used two approaches: (i) we titrated wt and deaminase-defective APO3G in transient-transfection studies to achieve similar levels of virus-associated APO3G and (ii) we constructed stable cell lines and selected clones expressing comparable amounts of wt and deaminase-defective APO3G. Viruses produced under these conditions were tested for viral infectivity. The results from the two approaches were consistent and suggested that the antiviral activity of deaminase-defective APO3G was significantly lower than that of wt APO3G. We conclude that efficient inhibition of vif-defective human immunodeficiency virus type 1 requires catalytically active APO3G.

scholarly journals Antiviral properties of palinavir, a potent inhibitor of the human immunodeficiency virus type 1 protease.

1997 ◽  
Vol 41 (5) ◽  
pp. 965-971 ◽  
Author(s):  
D Lamarre ◽  
G Croteau ◽  
E Wardrop ◽  
L Bourgon ◽  
D Thibeault ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Potent Inhibitor ◽  
Clinical Isolates ◽  
Target Cells ◽  
Immunodeficiency Virus ◽  
Hiv 1

Palinavir is a potent inhibitor of the human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) proteases. Replication of laboratory strains (HIV-1, HIV-2, and simian immunodeficiency virus) and HIV-1 clinical isolates is inhibited by palinavir with 50% effective concentrations ranging from 0.5 to 30 nM. The average cytotoxic concentration of palinavir (35 microM) in the various target cells indicates a favorable therapeutic index. Potent antiviral activity is retained with increased doses of virus and with clinical isolates resistant to zidovudine (AZT), didanosine (ddI), or nevirapine. Combinations of palinavir with either AZT, ddI, or nevirapine demonstrate synergy or additivity in the inhibition of HIV-1 replication. Palinavir retains anti-HIV-1 activity when administered postinfection until times subsequent to the reverse transcription step. In chronically infected CR-10 cells, palinavir blocks Gag precursor polyprotein processing completely, reducing greater than 99% of infectious particle production. The results indicate that the antiviral activity of palinavir is specific to inhibition of the viral protease and occurs at a late stage in the replicative cycle of HIV-1. On the basis of the potent in vitro activity, low-level cytotoxicity, and other data, palinavir was selected for in-depth preclinical evaluation.

scholarly journals Genetic Analysis of the Localization of APOBEC3F to Human Immunodeficiency Virus Type 1 Virion Cores

2014 ◽  
Vol 89 (4) ◽  
pp. 2415-2424 ◽  
Author(s):  
John P. Donahue ◽  
Rebecca T. Levinson ◽  
Jonathan H. Sheehan ◽  
Lorraine Sutton ◽  
Harry E. Taylor ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cytidine Deaminase ◽  
Cytidine Deaminases ◽  
Terminal Domain ◽  
Immunodeficiency Virus ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACTMembers of the APOBEC3 family of cytidine deaminases vary in their proportions of a virion-incorporated enzyme that is localized to mature retrovirus cores. We reported previously that APOBEC3F (A3F) was highly localized into mature human immunodeficiency virus type 1 (HIV-1) cores and identified that L306 in the C-terminal cytidine deaminase (CD) domain contributed to its core localization (C. Song, L. Sutton, M. Johnson, R. D'Aquila, J. Donahue, J Biol Chem287:16965–16974, 2012,http://dx.doi.org/10.1074/jbc.M111.310839). We have now determined an additional genetic determinant(s) for A3F localization to HIV-1 cores. We found that one pair of leucines in each of A3F's C-terminal and N-terminal CD domains jointly determined the degree of localization of A3F into HIV-1 virion cores. These are A3F L306/L368 (C-terminal domain) and A3F L122/L184 (N-terminal domain). Alterations to one of these specific leucine residues in either of the two A3F CD domains (A3F L368A, L122A, and L184A) decreased core localization and diminished HIV restriction without changing virion packaging. Furthermore, double mutants in these leucine residues in each of A3F's two CD domains (A3F L368A plus L184A or A3F L368A plus L122A) still were packaged into virions but completely lost core localization and anti-HIV activity. HIV virion core localization of A3F is genetically separable from its virion packaging, and anti-HIV activity requires some core localization.IMPORTANCESpecific leucine-leucine interactions are identified as necessary for A3F's core localization and anti-HIV activity but not for its packaging into virions. Understanding these signals may lead to novel strategies to enhance core localization that may augment effects of A3F against HIV and perhaps of other A3s against retroviruses, parvoviruses, and hepatitis B virus.

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