scholarly journals Budding of a Retrovirus: Some Assemblies Required

Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1188 ◽  
Author(s):  
Kevin M. Rose ◽  
Vanessa M. Hirsch ◽  
Fadila Bouamr
Keyword(s):  
Adaptor Protein ◽  
Particle Assembly ◽  
Endosomal Sorting ◽  
Peptide Motifs ◽  
Gag Polyprotein ◽  
Temporal Specificity ◽  
Cellular Machinery ◽  
Viral Lifecycle ◽  
Viral Particle Assembly ◽  
Shed Light

One of the most important steps in any viral lifecycle is the production of progeny virions. For retroviruses as well as other viruses, this step is a highly organized process that occurs with exquisite spatial and temporal specificity on the cellular plasma membrane. To facilitate this process, retroviruses encode short peptide motifs, or L domains, that hijack host factors to ensure completion of this critical step. One such cellular machinery targeted by viruses is known as the Endosomal Sorting Complex Required for Transport (ESCRTs). Typically responsible for vesicular trafficking within the cell, ESCRTs are co-opted by the retroviral Gag polyprotein to assist in viral particle assembly and release of infectious virions. This review in the Viruses Special Issue “The 11th International Retroviral Nucleocapsid and Assembly Symposium”, details recent findings that shed light on the molecular details of how ESCRTs and the ESCRT adaptor protein ALIX, facilitate retroviral dissemination at sites of viral assembly.

Are phytoplankton population density maxima predictable through analysis of host and viral genomic DNA content?

2006 ◽  
Vol 86 (3) ◽  
pp. 491-498 ◽  
Author(s):  
Chris M. Brown ◽  
Janice E. Lawrence ◽  
Douglas A. Campbell
Keyword(s):  
Population Density ◽  
Dna Content ◽  
Viral Genome ◽  
Particle Assembly ◽  
Phytoplankton Population ◽  
Strong Linear Correlation ◽  
Viral Progeny ◽  
A Cell ◽  
Viral Proliferation ◽  
Viral Particle Assembly

Phytoplankton:virus interactions are important factors in aquatic nutrient cycling and community succession. The number of viral progeny resulting from an infection of a cell critically influences the propagation of infection and concomitantly the dynamics of phytoplankton populations. Host nucleotide content may be the resource limiting viral particle assembly. We present evidence for a strong linear correlation between measured viral burst sizes and viral burst sizes predicted from the host DNA content divided by the viral genome size, across a diversity of phytoplankton:viral pairs. An analysis of genome sizes therefore supports predictions of taxon-specific phytoplankton population density thresholds beyond which viral proliferation can trim populations or terminate phytoplankton blooms. We present corollaries showing that host:virus interactions may place evolutionary pressure towards genome reduction of both phytoplankton hosts and their viruses.

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

2008 ◽  
Vol 82 (9) ◽  
pp. 4413-4419 ◽  
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.

scholarly journals Planar Cell Polarity Acts Through Septins to Control Collective Cell Movement and Ciliogenesis

Science ◽  
2010 ◽  
Vol 329 (5997) ◽  
pp. 1337-1340 ◽  
Author(s):  
Su Kyoung Kim ◽  
Asako Shindo ◽  
Tae Joo Park ◽  
Edwin C. Oh ◽  
Srimoyee Ghosh ◽  
...  
Keyword(s):  
Cell Polarity ◽  
Planar Cell Polarity ◽  
Control Point ◽  
Cell Movement ◽  
Cytoskeletal Proteins ◽  
Pcp Signaling ◽  
Cellular Machinery ◽  
And Migration ◽  
Controlling Behaviors ◽  
Shed Light

The planar cell polarity (PCP) signaling pathway governs collective cell movements during vertebrate embryogenesis, and certain PCP proteins are also implicated in the assembly of cilia. The septins are cytoskeletal proteins controlling behaviors such as cell division and migration. Here, we identified control of septin localization by the PCP protein Fritz as a crucial control point for both collective cell movement and ciliogenesis in Xenopus embryos. We also linked mutations in human Fritz to Bardet-Biedl and Meckel-Gruber syndromes, a notable link given that other genes mutated in these syndromes also influence collective cell movement and ciliogenesis. These findings shed light on the mechanisms by which fundamental cellular machinery, such as the cytoskeleton, is regulated during embryonic development and human disease.

scholarly journals Molecular Characterization of Feline Immunodeficiency Virus Budding

2007 ◽  
Vol 82 (5) ◽  
pp. 2106-2119 ◽  
Author(s):  
Benjamin G. Luttge ◽  
Miranda Shehu-Xhilaga ◽  
Dimiter G. Demirov ◽  
Catherine S. Adamson ◽  
Ferri Soheilian ◽  
...  
Keyword(s):  
Feline Immunodeficiency Virus ◽  
Equine Infectious Anemia Virus ◽  
Binding Motif ◽  
Virus Release ◽  
Related Sequence ◽  
Endosomal Sorting ◽  
Peptide Motifs ◽  
C Terminus ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Infection of domestic cats with feline immunodeficiency virus (FIV) is an important model system for studying human immunodeficiency virus type 1 (HIV-1) infection due to numerous similarities in pathogenesis induced by these two lentiviruses. However, many molecular aspects of FIV replication remain poorly understood. It is well established that retroviruses use short peptide motifs in Gag, known as late domains, to usurp cellular endosomal sorting machinery and promote virus release from infected cells. For example, the Pro-Thr/Ser-Ala-Pro [P(T/S)AP] motif of HIV-1 Gag interacts directly with Tsg101, a component of the endosomal sorting complex required for transport I (ESCRT-I). A Tyr-Pro-Asp-Leu (YPDL) motif in equine infectious anemia virus (EIAV), and a related sequence in HIV-1, bind the endosomal sorting factor Alix. In this study we sought to identify and characterize FIV late domain(s) and elucidate cellular machinery involved in FIV release. We determined that mutagenesis of a PSAP motif in FIV Gag, small interfering RNA-mediated knockdown of Tsg101 expression, and overexpression of a P(T/S)AP-binding fragment of Tsg101 (TSG-5′) each inhibited FIV release. We also observed direct binding of FIV Gag peptides to Tsg101. In contrast, mutagenesis of a potential Alix-binding motif in FIV Gag did not affect FIV release. Similarly, expression of the HIV-1/EIAV Gag-binding domain of Alix (Alix-V) did not disrupt FIV budding, and FIV Gag peptides showed no affinity for Alix-V. Our data demonstrate that FIV relies predominantly on a Tsg101-binding PSAP motif in the C terminus of Gag to promote virus release in HeLa cells, and this budding mechanism is highly conserved in feline cells.

scholarly journals The endosomal sorting adaptor HD-PTP is required for ephrin-B:EphB signalling in cell collapse and motor axon guidance

2018 ◽  
Author(s):  
Sylvie Lahaie ◽  
Daniel Morales ◽  
Halil Bagci ◽  
Noumeira Hamoud ◽  
Charles-Etienne Castonguay ◽  
...  
Keyword(s):  
Cultured Cells ◽  
Cell Communication ◽  
Adaptor Protein ◽  
Tyrosine Kinase Receptor ◽  
Kinase Activation ◽  
Surface Receptors ◽  
Endosomal Sorting ◽  
Mediate Cell ◽  
The Impact

AbstractThe signalling output of many transmembrane receptors that mediate cell-cell communication is restricted by the endosomal sorting complex required for transport (ESCRT), but the impact of this machinery on Eph tyrosine kinase receptor function is unknown. We identified the ESCRT-associated adaptor protein HD-PTP as part of an EphB2 BioID interactome, and confirmed this association using co-immunoprecipitation. Although HD-PTP loss does not change EphB2 expression, it attenuates the ephrin-B2:EphB2 signalling-induced collapse of cultured cells and axonal growth cones, and results in aberrant guidance of chick spinal motor neuron axons in vivo HD-PTP depletion abrogates ligand-induced EphB2 clustering, and EphB2 and Src family kinase activation. HD-PTP deficiency also accelerates ligand-induced EphB2 degradation, contrasting the phenotypes reported for other cell surface receptors. Our results link Eph signalling to the ESCRT machinery and demonstrate a role for HD-PTP in the earliest steps of ephrin-B:EphB signalling, as well as in obstructing premature receptor depletion.

scholarly journals Dengue virus capsid anchor modulates the efficiency of polyprotein processing and assembly of viral particles

2019 ◽  
Vol 100 (12) ◽  
pp. 1663-1673 ◽  
Author(s):  
Jyoti Rana ◽  
José Luis Slon Campos ◽  
Monica Poggianella ◽  
Oscar R. Burrone
Keyword(s):  
Dengue Virus ◽  
Structure Prediction ◽  
Secondary Structure Prediction ◽  
Sequence Length ◽  
Efficient Production ◽  
Processing Efficiency ◽  
Particle Assembly ◽  
Polyprotein Processing ◽  
Viral Polyprotein ◽  
Viral Particle Assembly

The assembly and secretion of flaviviruses are part of an elegantly regulated process. During maturation, the viral polyprotein undergoes several co- and post-translational cleavages mediated by both viral and host proteases. Among these, sequential cleavage at the N and C termini of the hydrophobic capsid anchor (Ca) is crucial in deciding the fate of viral infection. Here, using a refined dengue pseudovirus production system, along with cleavage and furin inhibition assays, immunoblotting and secondary structure prediction analysis, we show that Ca plays a key role in the processing efficiency of dengue virus type 2 (DENV2) structural proteins and viral particle assembly. Replacement of the DENV2 Ca with the homologous regions from West nile or Zika viruses or, alternatively, increasing its length, improved cleavage and hence particle assembly. Further, we showed that substitution of the Ca conserved proline residue (P110) to alanine abolishes pseudovirus production, regardless of the Ca sequence length. Besides providing the results of a biochemical analysis of DENV2 structural polyprotein processing, this study also presents a system for efficient production of dengue pseudoviruses.

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

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.

HIV-1 and Ebola virus encode small peptide motifs that recruit Tsg101 to sites of particle assembly to facilitate egress

2001 ◽  
Vol 7 (12) ◽  
pp. 1313-1319 ◽  
Author(s):  
Juan Martin-Serrano ◽  
Trinity Zang ◽  
Paul D. Bieniasz
Keyword(s):  
Ebola Virus ◽  
Small Peptide ◽  
Particle Assembly ◽  
Peptide Motifs ◽  
Hiv 1
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