Conformational Changes Of Gag HIV-1 On A Tethered Bilayer Measured By Neutron Reflectivity Provides Insights Into Viral Particle Assembly

The HIV-1 Gag protein is responsible for genomic RNA (gRNA) packaging and immature viral particle assembly. Although the presence of gRNA in virions is required for viral infectivity, in its absence, Gag can assemble around cellular RNAs and form particles resembling gRNA-containing particles. When gRNA is expressed, it is selectively packaged despite the presence of excess host RNA, but how it is selectively packaged is not understood. Specific recognition of a gRNA packaging signal (Psi) has been proposed to stimulate the efficient nucleation of viral assembly. However, the heterogeneity of Gag–RNA interactions renders capturing this transient nucleation complex using traditional structural biology approaches challenging. Here, we used native MS to investigate RNA binding of wild-type (WT) Gag and Gag lacking the p6 domain (GagΔp6). Both proteins bind to Psi RNA primarily as dimers, but to a control RNA primarily as monomers. The dimeric complexes on Psi RNA require an intact dimer interface within Gag. GagΔp6 binds to Psi RNA with high specificity in vitro and also selectively packages gRNA in particles produced in mammalian cells. These studies provide direct support for the idea that Gag binding to Psi specifically promotes nucleation of Gag–Gag interactions at the early stages of immature viral particle assembly in a p6-independent manner.

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HIV-1 Gag protein with or without p6 specifically dimerizes on the viral RNA packaging signal

10.1101/2020.06.18.159822 ◽

2020 ◽

Author(s):

Samantha Sarni ◽

Banhi Biswas ◽

Shuohui Liu ◽

Erik D. Olson ◽

Jonathan P. Kitzrow ◽

...

Keyword(s):

Mammalian Cells ◽

Viral Particle ◽

Rna Binding ◽

Packaging Signal ◽

Independent Manner ◽

Particle Assembly ◽

Gag Protein ◽

Viral Particle Assembly ◽

Hiv 1 ◽

Psi Rna

AbstractThe HIV-1 Gag protein is responsible for genomic RNA (gRNA) packaging and immature viral particle assembly. While the presence of gRNA in virions is required for viral infectivity, in its absence, Gag can assemble around cellular RNAs and form particles resembling gRNA-containing particles. When gRNA is expressed, it is selectively packaged despite the presence of excess host RNA, but how it is selectively packaged is not understood. Specific recognition of a gRNA packaging signal (Psi) has been proposed to stimulate the efficient nucleation of viral assembly. However, the heterogeneity of Gag-RNA interactions renders capturing this transient nucleation complex using traditional structural biology approaches challenging. Here, we used native mass spectrometry to investigate RNA binding of wild-type Gag and Gag lacking the p6 domain (GagΔp6). Both proteins bind to Psi RNA primarily as dimers, but to a control RNA primarily as monomers. The dimeric complexes on Psi RNA require an intact dimer interface within Gag. GagΔp6 binds to Psi RNA with high specificity in vitro and also selectively packages gRNA in particles produced in mammalian cells. These studies provide direct support for the idea that Gag binding to Psi specifically nucleates Gag-Gag interactions at the early stages of immature viral particle assembly in a p6-independent manner.

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The Amino-Terminal Domain of Alphavirus Capsid Protein Is Dispensable for Viral Particle Assembly but Regulates RNA Encapsidation through Cooperative Functions of Its Subdomains

Journal of Virology ◽

10.1128/jvi.01960-13 ◽

2013 ◽

Vol 87 (22) ◽

pp. 12003-12019 ◽

Cited By ~ 22

Author(s):

V. Lulla ◽

D. Y. Kim ◽

E. I. Frolova ◽

I. Frolov

Keyword(s):

Capsid Protein ◽

Viral Particle ◽

Particle Assembly ◽

Amino Terminal ◽

Terminal Domain ◽

Amino Terminal Domain ◽

Viral Particle Assembly

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The GLN Family of Murine Endogenous Retroviruses Contains an Element Competent for Infectious Viral Particle Formation

Journal of Virology ◽

10.1128/jvi.02141-07 ◽

2008 ◽

Vol 82 (9) ◽

pp. 4413-4419 ◽

Cited By ~ 9

Author(s):

David Ribet ◽

Francis Harper ◽

Cécile Esnault ◽

Gérard Pierron ◽

Thierry Heidmann

Keyword(s):

Viral Particle ◽

Leukemia Virus ◽

Endogenous Retroviruses ◽

Particle Assembly ◽

New Class ◽

Mouse Mammary Tumor ◽

The Family ◽

Tumor Virus ◽

Mouse Cells ◽

Viral Particle Assembly

ABSTRACT Several families of endogenous retroviruses (ERVs) have been identified in the mouse genome, in several instances by in silico searches, but for many of them it remains to be determined whether there are elements that can still encode functional retroviral particles. Here, we identify, within the GLN family of highly reiterated ERVs, one, and only one, copy that encodes retroviral particles prone to infection of mouse cells. We show that its envelope protein confers an ecotropic host range and recognizes a receptor different from mCAT1 and mSMIT1, the two previously identified receptors for other ecotropic mouse retroviruses. Electron microscopy disclosed viral particle assembly and budding at the cell membrane, as well as release of mature particles into the extracellular space. These particles are closely related to murine leukemia virus (MLV) particles, with which they have most probably been confused in the past. This study, therefore, identifies a new class of infectious mouse ERVs belonging to the family Gammaretroviridae, with one family member still functional today. This family is in addition to the two MLV and mouse mammary tumor virus families of active mouse ERVs with an extracellular life cycle.

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HIV Gag polyprotein: processing and early viral particle assembly

Trends in Microbiology ◽

10.1016/j.tim.2012.11.006 ◽

2013 ◽

Vol 21 (3) ◽

pp. 136-144 ◽

Cited By ~ 127

Author(s):

Neil M. Bell ◽

Andrew M.L. Lever

Keyword(s):

Viral Particle ◽

Particle Assembly ◽

Polyprotein Processing ◽

Gag Polyprotein ◽

Viral Particle Assembly

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Rational pharmacological approach to clinical studies for the treatment of SARS-COV-2 infection

Enfermagem Brasil ◽

10.33233/eb.v19i4.4349 ◽

2020 ◽

Vol 19 (4) ◽

pp. 42

Author(s):

Antônia Dailane Dos Santos Rabêlo ◽

Gizelle Gomes De Souza ◽

Rosilene Ribeiro De Sousa ◽

Charllyton Luis Sena Da Costa

Keyword(s):

Viral Particle ◽

Scientific Information ◽

Lessons Learned ◽

Cell Replication ◽

Particle Assembly ◽

Rational Combination ◽

Different Populations ◽

Multiple Drugs ◽

Molecular Components ◽

Viral Particle Assembly

AbstractThe global emergency generated by the COVID-19 pandemic caused by the SARS-COV-2 virus has created serious impacts on the different populations of the planet and has triggered the generation of scientific information on an unprecedented scale until then for a single topic. One of the consequences of the global scientific effort lies in the large number of substances already tested, by different methods, the search for an effective treatment for the infection and the consequent disease, remaining without absolute success so far. Assimilating the lessons, learned from the successful adoption of therapies combining multiple drugs used in HIV infection, the evidence obtained from the large amount of published information regarding the action of many substances with different mechanisms, now allows the proposition, in this work, of tests clinical trials for the evaluation of regimens composed of at least three drugs in combination. Rational combination schemes can target different molecular components of the virus affecting different points in the SARS-COV-2 replication cycle, such as virus fusion to the host cell, replication and viral particle assembly generating a potentially more effective synergistic effect than attempts using a single substance.Keywords: antiviral, pandemic, combination therapy.

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Structural determinants of virion assembly and release in the C-terminus of the M-PMV capsid protein

Journal of Virology ◽

10.1128/jvi.00615-21 ◽

2021 ◽

Author(s):

Marlene V. Buckmaster ◽

Kaneil K. Zadrozny ◽

Barbie K. Ganser-Pornillos ◽

Owen Pornillos ◽

Stephen P. Goff

Keyword(s):

Capsid Protein ◽

Conformational Changes ◽

Structural Determinants ◽

Particle Assembly ◽

Gag Protein ◽

Virion Assembly ◽

C Terminus ◽

Hiv 1

The transition from an immature to a fully infectious mature retrovirus particle is associated with molecular switches that trigger dramatic conformational changes in the structure of the Gag proteins. A dominant maturation switch that stabilizes the immature capsid lattice is located downstream of the capsid (CA) protein in many retroviral Gags. The HIV-1 Gag contains a stretch of five amino acid residues termed the ‘clasp motif’, important for the organization of the hexameric subunits that provide stability to the overall immature HIV-1 shell. Sequence alignment of the CA C-terminal domains (CTDs) of the HIV-1 and Mason-Pfizer Monkey Virus (M-PMV) highlighted a spacer-like domain in M-PMV that may provide comparable function. The importance of the sequences spanning the CA-NC cleavage has been demonstrated by mutagenesis, but the specific requirements for the clasp motif in several steps of M-PMV particle assembly and maturation have not been determined in detail. In the present study we report an examination of the role of the clasp motif in the M-PMV life cycle. We generated a series of M-PMV Gag mutants and assayed for assembly of the recombinant protein in vitro , and for the assembly, maturation, release, genomic RNA packaging, and infectivity of the mutant virus in vivo . The mutants revealed major defects in virion assembly and release in 293T and HeLa cells, and even larger defects in infectivity. Our data identifies the clasp motif as a fundamental contributor to CA-CTD interactions necessary for efficient viral infection. Importance The C-terminal domain of the capsid protein of many retroviruses has been shown to be critical for virion assembly and maturation, but the functions of this region of M-PMV are uncertain. We show that a short ‘clasp’ motif in the capsid domain of the M-PMV Gag protein plays a key role in M-PMV virion assembly, genome packaging, and infectivity.

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