scholarly journals Role of HIV-1 RNA and protein determinants for the selective packaging of spliced and unspliced viral RNA and host U6 and 7SL RNA in virus particles

2011 ◽  
Vol 39 (20) ◽  
pp. 8915-8927 ◽  
Author(s):  
L. Didierlaurent ◽  
P. J. Racine ◽  
L. Houzet ◽  
C. Chamontin ◽  
B. Berkhout ◽  
...  
Keyword(s):  
Viral Rna ◽  
Virus Particles ◽  
7Sl Rna ◽  
Hiv 1

scholarly journals Going beyond Integration: The Emerging Role of HIV-1 Integrase in Virion Morphogenesis

Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1005 ◽  
Author(s):  
Jennifer L. Elliott ◽  
Sebla B. Kutluay
Keyword(s):  
Life Cycle ◽  
Viral Genome ◽  
Critical Role ◽  
Viral Rna ◽  
Target Cells ◽  
Host Chromosome ◽  
Virion Morphogenesis ◽  
Rna Genome ◽  
Hiv 1

The HIV-1 integrase enzyme (IN) plays a critical role in the viral life cycle by integrating the reverse-transcribed viral DNA into the host chromosome. This function of IN has been well studied, and the knowledge gained has informed the design of small molecule inhibitors that now form key components of antiretroviral therapy regimens. Recent discoveries unveiled that IN has an under-studied yet equally vital second function in human immunodeficiency virus type 1 (HIV-1) replication. This involves IN binding to the viral RNA genome in virions, which is necessary for proper virion maturation and morphogenesis. Inhibition of IN binding to the viral RNA genome results in mislocalization of the viral genome inside the virus particle, and its premature exposure and degradation in target cells. The roles of IN in integration and virion morphogenesis share a number of common elements, including interaction with viral nucleic acids and assembly of higher-order IN multimers. Herein we describe these two functions of IN within the context of the HIV-1 life cycle, how IN binding to the viral genome is coordinated by the major structural protein, Gag, and discuss the value of targeting the second role of IN in virion morphogenesis.

scholarly journals Dissociation of Genome Dimerization from Packaging Functions and Virion Maturation of Human Immunodeficiency Virus Type 1

2002 ◽  
Vol 76 (3) ◽  
pp. 959-967 ◽  
Author(s):  
Jun-ichi Sakuragi ◽  
Aikichi Iwamoto ◽  
Tatsuo Shioda
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Rna ◽  
Rna Packaging ◽  
Virus Particles ◽  
Immunodeficiency Virus ◽  
Rna Interaction ◽  
Hiv 1

ABSTRACT The dimer initiation site/dimer linkage sequence (DIS/DLS) region of the human immunodeficiency virus type 1 (HIV-1) RNA genome is thought to play important roles at various stages of the virus life cycle. Recently we showed that the DIS/DLS region affects RNA-RNA interaction in intact virus particles, by demonstrating that duplication of the region in viral RNA caused the production of virus particles containing partially monomeric RNAs. We have extended this finding and succeeded for the first time in creating mutant particles which contain only monomeric RNAs without modifying any viral proteins. In terms of RNA encapsidation ability, virion density, and protein processing, the mutant particles were comparable to wild-type particles. The level of production of viral DNA by the mutant virus construct in infected cells was also comparable to that of the constructs that produced exclusively dimeric RNA, indicating that monomeric viral RNA could be the template for strand transfer. These results indicated that the RNA dimerization of HIV-1 could be separated from viral RNA packaging and was not absolutely required for RNA packaging, virion maturation, and reverse transcription.

scholarly journals Infectious and Whole Inactivated Simian Immunodeficiency Viruses Interact Similarly with Primate Dendritic Cells (DCs): Differential Intracellular Fate of Virions in Mature and Immature DCs

2002 ◽  
Vol 76 (6) ◽  
pp. 2936-2951 ◽  
Author(s):  
I. Frank ◽  
M. Piatak ◽  
H. Stoessel ◽  
N. Romani ◽  
D. Bonnyay ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Viral Rna ◽  
Virus Particles ◽  
Large Numbers ◽  
Heat Treated ◽  
Intact Virus ◽  
Immunodeficiency Virus ◽  
Spread Of Infection ◽  
Virus Interactions ◽  
Hiv 1

ABSTRACT As potential targets for human immunodeficiency virus type 1 and simian immunodeficiency virus (HIV-1 and SIV), dendritic cells (DCs) likely play a significant role in the onset and spread of infection as well as in the induction of antiviral immunity. Using the SIV-macaque system to study the very early events in DC-virus interactions, we compared chemically inactivated SIV having conformationally and functionally intact envelope glycoproteins (2,2′-dithiodipyridine [AT-2] SIV) to infectious and heat-treated SIV. Both human and macaque DCs interact similarly with SIV without detectable effects on DC viability, phenotype, or endocytic function. As assessed by measuring cell-associated viral RNA, considerable amounts of virus are captured by the DCs and this is reduced when the virus is heat treated or derived from a strain that expresses low levels of envelope glycoprotein. Immunostaining for SIV proteins and electron microscopy indicated that few intact virus particles are retained at the periphery of the endocytically active, immature DCs. This contrasts with a perinuclear localization of numerous virions in large vesicular compartments deeper within mature DCs (in which macropinocytosis is down-regulated). Both immature and mature DCs are capable of clathrin-coated pit-mediated uptake of SIV, supporting the notion that the receptor-mediated uptake of virus can occur readily in mature DCs. While large numbers of whole viruses were preferentially found in mature DCs, both immature and mature DCs contained similar amounts of viral RNA, suggesting that different uptake/virus entry mechanisms are active in immature and mature DCs. These findings have significant implications for cell-to-cell transmission of HIV-1 and SIV and support the use of AT-2 SIV, an authentic but noninfectious form of virus, as a useful tool for studies of processing and presentation of AT-2 SIV antigens by DCs.

scholarly journals Integrase-RNA interactions underscore the critical role of integrase in HIV-1 virion morphogenesis

2019 ◽  
Author(s):  
Jennifer Elliott ◽  
Jenna E. Eschbach ◽  
Pratibha C. Koneru ◽  
Wen Li ◽  
Maritza Puray Chavez ◽  
...  
Keyword(s):  
Rna Binding ◽  
Critical Role ◽  
Underlying Mechanism ◽  
Class Ii ◽  
Viral Rna ◽  
Target Cells ◽  
Ribonucleoprotein Complexes ◽  
Virion Morphogenesis ◽  
Hiv 1

ABSTRACTA large number of HIV-1 integrase (IN) alterations, referred to as class II substitutions, exhibit pleotropic effects during virus replication. However, the underlying mechanism for the class II phenotype is not known. Here we demonstrate that all tested class II IN substitutions compromised IN-RNA binding in virions by one of three distinct mechanisms: i) markedly reducing IN levels thus precluding formation of IN complexes with viral RNA; ii) adversely affecting functional IN multimerization and consequently impairing IN binding to viral RNA; iii) directly compromising IN-RNA interactions without substantially affecting IN levels or functional IN multimerization. Inhibition of IN-RNA interactions resulted in mislocalization of the viral ribonucleoprotein complexes outside the capsid lattice, which led to premature degradation of the viral genome and IN in target cells. Collectively, our studies uncover causal mechanisms for the class II phenotype and highlight an essential role of IN-RNA interactions for accurate virion maturation.

scholarly journals Elucidating the basis for permissivity of the MT-4 T-cell line to replication of an HIV-1 mutant lacking the gp41 cytoplasmic tail

2020 ◽  
Author(s):  
Melissa V. Fernandez ◽  
Huxley K. Hoffman ◽  
Nairi Pezeshkian ◽  
Philip R. Tedbury ◽  
Schuyler B. van Engelenburg ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Cytoplasmic Tail ◽  
Viral Transmission ◽  
Virus Particles ◽  
Cell Transmission ◽  
T Cell Lines ◽  
Hiv 1

AbstractHIV-1 encodes an envelope glycoprotein (Env) that contains a long cytoplasmic tail (CT) harboring trafficking motifs implicated in Env incorporation into virus particles and viral transmission. In most physiologically relevant cell types, the gp41 CT is required for HIV-1 replication, but in the MT-4 T-cell line the gp41 CT is not required for a spreading infection. To help elucidate the role of the gp41 CT in HIV-1 transmission, in this study we investigated the viral and cellular factors that contribute to the permissivity of MT-4 to gp41 CT truncation. We found that the kinetics of HIV-1 production are faster in MT-4 than in the other T-cell lines tested, but MT-4 express equivalent amounts of HIV-1 proteins on a per-cell basis relative to cells not permissive to CT truncation. MT-4 express higher levels of plasma-membrane-associated Env than non-permissive cells and Env internalization from the plasma membrane is slower compared to another T-cell line, SupT1. Paradoxically, despite the high levels of Env on the surface of MT-4, two-fold less Env is incorporated into virus particles in MT-4 compared to SupT1. Cell-to-cell transmission between co-cultured 293T and MT-4 is higher than in co-cultures of 293T with most other T-cell lines tested, indicating that MT-4 are highly susceptible to this mode of infection. These data help to clarify the long-standing question of how MT-4 cells overcome the requirement for the HIV-1 gp41 CT and support a role for gp41 CT-dependent trafficking in Env incorporation and cell-to-cell transmission in physiologically relevant cell lines.ImportanceThe HIV-1 Env cytoplasmic tail (CT) is required for efficient Env incorporation into nascent particles and viral transmission in primary CD4+ T cells. The MT-4 T-cell line has been reported to support multiple rounds of infection of HIV-1 encoding a gp41 CT truncation. Uncovering the underlying mechanism of MT-4 T-cell line permissivity to gp41 CT truncation would provide key insights into the role of the gp41 CT in HIV-1 transmission. This study reveals that multiple factors contribute to the unique ability of a gp41 CT truncation mutant to spread in cultures of MT-4 cells. The lack of a requirement for the gp41 CT in MT-4 is associated with the combined effects of rapid HIV-1 protein production, high levels of cell-surface Env expression, and increased susceptibility to cell-to-cell transmission compared to non-permissive cells.

scholarly journals Integrase-RNA interactions underscore the critical role of integrase in HIV-1 virion morphogenesis

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Jennifer L Elliott ◽  
Jenna E Eschbach ◽  
Pratibha C Koneru ◽  
Wen Li ◽  
Maritza Puray-Chavez ◽  
...  
Keyword(s):  
Rna Binding ◽  
Critical Role ◽  
Underlying Mechanism ◽  
Class Ii ◽  
Viral Rna ◽  
Target Cells ◽  
Ribonucleoprotein Complexes ◽  
Immunodeficiency Virus ◽  
Hiv 1

A large number of human immunodeficiency virus 1 (HIV-1) integrase (IN) alterations, referred to as class II substitutions, exhibit pleiotropic effects during virus replication. However, the underlying mechanism for the class II phenotype is not known. Here we demonstrate that all tested class II IN substitutions compromised IN-RNA binding in virions by one of the three distinct mechanisms: (i) markedly reducing IN levels thus precluding the formation of IN complexes with viral RNA; (ii) adversely affecting functional IN multimerization and consequently impairing IN binding to viral RNA; and (iii) directly compromising IN-RNA interactions without substantially affecting IN levels or functional IN multimerization. Inhibition of IN-RNA interactions resulted in the mislocalization of viral ribonucleoprotein complexes outside the capsid lattice, which led to premature degradation of the viral genome and IN in target cells. Collectively, our studies uncover causal mechanisms for the class II phenotype and highlight an essential role of IN-RNA interactions for accurate virion maturation.

scholarly journals Extracellular Vesicles in Viral Infections of the Nervous System

Viruses ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 700 ◽  
Author(s):  
Naseer A. Kutchy ◽  
Eric S. Peeples ◽  
Susmita Sil ◽  
Ke Liao ◽  
Ernest T. Chivero ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Viral Infections ◽  
Virus Particles ◽  
Pathological Conditions ◽  
Current Review ◽  
Membrane Bound ◽  
Mediate Cell ◽  
Almost All ◽  
Hiv 1

Almost all types of cells release extracellular vesicles (EVs) into the extracellular space. EVs such as exosomes and microvesicles are membrane-bound vesicles ranging in size from 30 to 1000 nm in diameter. Under normal conditions, EVs mediate cell to cell as well as inter-organ communication via the shuttling of their cargoes which include RNA, DNA and proteins. Under pathological conditions, however, the number, size and content of EVs are found to be altered and have been shown to play crucial roles in disease progression. Emerging studies have demonstrated that EVs are involved in many aspects of viral infection-mediated neurodegenerative diseases. In the current review, we will describe the interactions between EV biogenesis and the release of virus particles while also reviewing the role of EVs in various viral infections, such as HIV-1, HTLV, Zika, CMV, EBV, Hepatitis B and C, JCV, and HSV-1. We will also discuss the potential uses of EVs and their cargoes as biomarkers and therapeutic vehicles for viral infections.

scholarly journals Elucidating the Basis for Permissivity of the MT-4 T-Cell Line to Replication of an HIV-1 Mutant Lacking the gp41 Cytoplasmic Tail

2020 ◽  
Vol 94 (23) ◽  
Author(s):  
Melissa V. Fernandez ◽  
Huxley K. Hoffman ◽  
Nairi Pezeshkian ◽  
Philip R. Tedbury ◽  
Schuyler B. van Engelenburg ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Cytoplasmic Tail ◽  
Viral Transmission ◽  
Virus Particles ◽  
T Cell Lines ◽  
Hiv 1

ABSTRACT HIV-1 encodes an envelope glycoprotein (Env) that contains a long cytoplasmic tail (CT) harboring trafficking motifs implicated in Env incorporation into virus particles and viral transmission. In most physiologically relevant cell types, the gp41 CT is required for HIV-1 replication, but in the MT-4 T-cell line the gp41 CT is not required for a spreading infection. To help elucidate the role of the gp41 CT in HIV-1 transmission, in this study, we investigated the viral and cellular factors that contribute to the permissivity of MT-4 cells to gp41 CT truncation. We found that the kinetics of HIV-1 production and virus release are faster in MT-4 than in the other T-cell lines tested, but MT-4 cells express equivalent amounts of HIV-1 proteins on a per-cell basis relative to cells not permissive to CT truncation. MT-4 cells express higher levels of plasma-membrane-associated Env than nonpermissive cells, and Env internalization from the plasma membrane is less efficient than that from another T-cell line, SupT1. Paradoxically, despite the high levels of Env on the surface of MT-4 cells, 2-fold less Env is incorporated into virus particles produced from MT-4 than SupT1 cells. Contact-dependent transmission between cocultured 293T and MT-4 cells is higher than in cocultures of 293T with most other T-cell lines tested, indicating that MT-4 cells are highly susceptible to cell-to-cell infection. These data help to clarify the long-standing question of how MT-4 cells overcome the requirement for the HIV-1 gp41 CT and support a role for gp41 CT-dependent trafficking in Env incorporation and cell-to-cell transmission in physiologically relevant cell lines. IMPORTANCE The HIV-1 Env cytoplasmic tail (CT) is required for efficient Env incorporation into nascent particles and viral transmission in primary CD4+ T cells. The MT-4 T-cell line has been reported to support multiple rounds of infection of HIV-1 encoding a gp41 CT truncation. Uncovering the underlying mechanism of MT-4 T-cell line permissivity to gp41 CT truncation would provide key insights into the role of the gp41 CT in HIV-1 transmission. This study reveals that multiple factors contribute to the unique ability of a gp41 CT truncation mutant to spread in cultures of MT-4 cells. The lack of a requirement for the gp41 CT in MT-4 cells is associated with the combined effects of rapid HIV-1 protein production, high levels of cell-surface Env expression, and increased susceptibility to cell-to-cell transmission compared to nonpermissive cells.

scholarly journals Control of Human Immunodeficiency Virus Type 1 RNA Metabolism: Role of Splice Sites and Intron Sequences in Unspliced Viral RNA Subcellular Distribution

1998 ◽  
Vol 72 (12) ◽  
pp. 9503-9513 ◽  
Author(s):  
Béatrice Séguin ◽  
Alfredo Staffa ◽  
Alan Cochrane
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Subcellular Distribution ◽  
Viral Rna ◽  
Splice Sites ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT In the course of examining the various factors which affect the metabolism of human immunodeficiency virus type 1 (HIV-1) RNA, we examined the role of intron sequences and splice sites in determining the subcellular distribution of the RNA. Using in situ hybridization, we demonstrated that in the absence of Rev, unspliced RNA generated with an HIV-1 env expression construct displayed discrete localization in the nucleus, coincident with the location of the gene and not associated with SC35-containing nuclear speckles. Expression of Rev resulted in a disperse signal for the unspliced RNA throughout both the nucleus and the cytoplasm. Subsequent fractionation of the nucleus revealed that the majority of unspliced viral RNA within the nucleus is associated with the nuclear matrix and that upon expression of Rev, a small proportion of the unspliced RNA is found within the nucleoplasm. Mutations which altered splice site utilization did not alter the sequestration of unspliced RNA into discrete nuclear regions. In contrast, a 2.2-kb deletion of intron sequence resulted in a shift from discrete regions within the nucleus to a disperse signal throughout the cell, indicating that intron sequences, and not just splice sites, are required for the observed nuclear sequestration of unspliced viral RNA.

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