Herpes simplex virus type 1 cytoplasmic envelopment requires functional Vps4.
Ontology highlight
ABSTRACT:
SUBMITTER: Crump CM
PROVIDER: S-EPMC1933334 | biostudies-literature | 2007 Jul
REPOSITORIES: biostudies-literature
Publications
Herpes simplex virus type 1 cytoplasmic envelopment requires functional Vps4.
Crump Colin M CM Yates Catherine C Minson Tony T
Journal of virology 20070516 14
The assembly and egress of herpesviruses are complex processes that require the budding of viral nucleocapsids into the lumen of cytoplasmic compartments to form mature infectious virus. This envelopment stage shares many characteristics with the formation of luminal vesicles in multivesicular endosomes. Through expression of dominant-negative Vps4, an enzyme that is essential for the formation of luminal vesicles in multivesicular endosomes, we now show that Vps4 function is required for the cy ...[more]
Similar Datasets
Project description:Herpes simplex virus 1 (HSV-1) viral glycoproteins gD (carboxyl terminus), gE, gK, and gM, the membrane protein UL20, and membrane-associated protein UL11 play important roles in cytoplasmic virion envelopment and egress from infected cells. We showed previously that a recombinant virus carrying a deletion of the carboxyl-terminal 29 amino acids of gD (gD?ct) and the entire gE gene (?gE) did not exhibit substantial defects in cytoplasmic virion envelopment and egress (H. C. Lee et al., J. Virol. 83:6115-6124, 2009). The recombinant virus ?gM2, engineered not to express gM, produced a 3- to 4-fold decrease in viral titers and a 50% reduction in average plaque sizes in comparison to the HSV-1(F) parental virus. The recombinant virus containing all three mutations, gD?ct-?gM2-?gE, replicated approximately 1 log unit less efficiently than the HSV-1(F) parental virus and produced viral plaques which were on average one-third the size of those of HSV-1(F). The recombinant virus ?UL11-?gM2, engineered not to express either UL11 or gM, replicated more than 1 log unit less efficiently and produced significantly smaller plaques than UL11-null or gM-null viruses alone, in agreement with the results of Leege et al. (T. Leege et al., J. Virol. 83:896-907, 2009). Analyses of particle-to-PFU ratios, relative plaque size, and kinetics of virus growth and ultrastructural visualization of glycoprotein-deficient mutant and wild-type virions indicate that gD?ct, gE, and gM function in a cooperative but not redundant manner in infectious virion morphogenesis. Overall, comparisons of single, double, and triple mutant viruses generated in the same HSV-1(F) genetic background indicated that lack of either UL20 or gK expression caused the most severe defects in cytoplasmic envelopment, egress, and infectious virus production, followed by the double deletion of UL11 and gM.
| S-EPMC3318672 | biostudies-literature
Project description:The herpes simplex virus type 1 UL20 protein (UL20p) is an important determinant for cytoplasmic virion morphogenesis and virus-induced cell fusion. To delineate the functional domains of the UL20 protein, we generated a panel of single and multiple (cluster) alanine substitutions as well as UL20p carboxyl-terminal truncations. The UL20 mutant genes could be broadly categorized into four main groups: Group I UL20 mutant genes complemented for both virus production and virus-induced cell fusion; Group II UL20 mutant genes did not complement for either virus-induced cell fusion or infectious virus production; Group III UL20 mutant genes complemented for virus-induced cell fusion to variable extents but exhibited substantially decreased ability to complement UL20-null infectious virus production; Group IV mutant genes complemented for infectious virus production but had variable effects on virus-induced cell fusion; this group included two mutants that efficiently complemented for gBsyn3, but not for gKsyn1, virus-induced cell fusion. In addition, certain recombinant viruses with mutations in either the amino or carboxyl termini of UL20p produced partially syncytial plaques on Vero cells in the absence of any other virally encoded syncytial mutations. These studies indicated that the amino and carboxyl termini of UL20p contained domains that functioned both in infectious virus production and virus-induced cell fusion. Moreover, the data suggested that the UL20p's role in virus-induced cell fusion can be functionally separated from its role in cytoplasmic virion morphogenesis and that certain UL20p domains that function in gB-syn3 virus-induced cell fusion are distinct from those functioning in gKsyn1 virus-induced cell fusion.
| S-EPMC434089 | biostudies-literature
Project description:The herpes simplex virus type 1 (HSV-1) US3 kinase is likely important for primary envelopment of progeny nucleocapsids since it localizes to the nuclear envelope of infected cells and largely determines the phosphorylation state and localization of the necessary primary envelopment factor, the UL34 protein. In HEp-2 cells, the production of infectious US3 null progeny is delayed and decreased relative to that of the parental strain, HSV-1(F). Furthermore, the US3 kinase affects the morphology of primary envelopment such that in its absence, UL34 protein-containing enveloped virions accumulate within membrane-bound vesicles. These vesicles are most often found along the interior periphery of the nucleus and may be derived from the inner nuclear membrane. Since the US3 and UL34 proteins comprise a kinase-substrate pair, a reasonable hypothesis is that the US3 kinase influences these replication parameters by direct phosphorylation of the UL34 protein. For this report, recombinant viruses were constructed to determine the significance of UL34 protein phosphorylation and US3 catalytic activity on UL34 protein localization, single-step growth, and envelopment morphology in both HEp-2 and Vero cells. The data presented suggest that the significance of UL34 phosphorylation is cell type dependent and that efficient viral morphogenesis requires US3-mediated phosphorylation of an infected cell protein other than UL34.
| S-EPMC303423 | biostudies-literature
Project description:Interferons (IFNs) and autophagy are critical neuronal defenses against viral infection. IFNs alter neuronal autophagy by promoting the accumulation of IFN-dependent LC3-decorated autophagic structures, termed LC3 clusters. Here, we analyzed LC3 clusters in sensory ganglia following herpes simplex virus 1 (HSV-1) infection. In the vicinity of acutely infected neurons, antigen-negative neurons contained structures resembling accumulated autophagosomes and autolysosomes that culminated in LC3 clusters. This accumulation reflects a delayed completion of autophagy. The endosomal sorting complexes required for transport (ESCRT) machinery participates in autophagosome closure and is also required for HSV-1 replication. In this study, our results showed that HSV-1 infection in vivo and in primary neurons caused a decrease in Vps4 (a key ESCRT pathway ATPase) RNA and protein with concomitant Stat1 activation and LC3 cluster induction. We also observed that IFNs were sufficient to decrease RNA and protein levels of Vps4 in primary neurons and in other cell types. The accumulation of ubiquitin was also observed at the LC3 cluster sites. Together, our results show that IFNs modulate the ESCRT machinery in neurons in response to HSV-1 infections.IMPORTANCE Neurons rely on IFNs and autophagy as major defenses against viral infections, and HSV must overcome such defenses in order to replicate. In addition to controlling host immunity, HSV must also control host membranes in order to complete its life cycle. HSV uses the host ESCRT membrane scission machinery for viral production and transport. Here we present evidence of a new IFN-dependent mechanism used by the host to prevent ESCRT subversion by HSV. This activity also impacts the dynamics of autophagy, possibly explaining the presence of recently described LC3 clusters in the HSV-infected nervous system. The induced accumulations of ubiquitin observed in these LC3 clusters resembled those observed in certain neurodegenerative diseases, suggesting possible mechanistic parallels between these conditions.
| S-EPMC6401484 | biostudies-literature
Project description:Herpes simplex virus type 1 (HSV-1) acquires its mature virus envelope by budding into the lumen of cytoplasmic membranous compartments carrying the viral glycoproteins. In a cellular context, a budding process with identical topology occurs during the formation of intraluminal vesicles in multivesicular bodies. The cellular machinery that mediates this budding process is composed of four protein complexes termed endosomal sorting complexes required for transport (ESCRTs) and several associated proteins, including the ATPase VPS4. We have recently shown that functional VPS4 is specifically required for the cytoplasmic envelopment of HSV-1. We now demonstrate that, consistent with a role of VPS4 in virus envelopment, dominant-negative ESCRT-III proteins potently block HSV-1 production. Retroviruses are known to recruit the ESCRT machinery by small peptide motifs termed late domains. These late domains interact with various ESCRT components and thereby promote ESCRT recruitment. The best-characterized late-domain interacting ESCRT proteins are ALIX and TSG101. The presence of potential ALIX and TSG101 binding sequence motifs in various structural HSV-1 proteins suggested a functional role of these proteins in HSV-1 envelopment. We therefore used a set of dominant-negative proteins, as well as RNA interference, to characterize the contribution of ALIX and TSG101 to HSV-1 production. Interestingly, despite the strict requirement for a functional ESCRT-III complex, our data suggest that HSV-1 production is independent of ALIX and TSG101 expression. In line with these data, we also find that ESCRT-III proteins and VPS4A/B are specifically incorporated into mature HSV-1 virions.
| S-EPMC2772754 | biostudies-literature
Project description:Infections with herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are a global health burden. Besides painful oral or genital lesions in otherwise healthy subjects, both viruses can cause devastating morbidity and mortality in immune-compromised and immune-immature individuals. The latter are particularly susceptible to a disseminated, life-threatening disease. Neutralizing antibodies (NAb) constitute a correlate of protection from disease, and are promising candidates for the prophylactic or therapeutic treatment of severe HSV infections. However, a clinical vaccine trial suggested that HSV-2 might be more resistant to NAbs than HSV-1. In the present study, we investigated the antiviral efficacy of the well-characterized humanized monoclonal antibody (mAb) hu2c against HSV-2, in a NOD/SCID immunodeficiency mouse model. Despite the fact that hu2c recognizes a fully conserved epitope and binds HSV-1 and HSV-2 glycoprotein B with equal affinity, it was much less effective against HSV-2 in vitro and in NOD/SCID mice. Although intravenous antibody treatment prolonged the survival of HSV-2-infected mice, complete protection from death was not achieved. Our data demonstrate that HSV-2 is more resistant to NAbs than HSV-1, even if the same antibody and antigen are concerned, making the development of a vaccine or therapeutic antibodies more challenging.
| S-EPMC7563860 | biostudies-literature
Project description:The herpes simplex virus 1 (HSV-1) UL37 protein functions in virion envelopment at trans-Golgi membranes, as well as in retrograde and anterograde transport of virion capsids. Recently, we reported that UL37 interacts with glycoprotein K (gK) and its interacting partner protein UL20 (N. Jambunathan, D. Chouljenko, P. Desai, A. S. Charles, R. Subramanian, V. N. Chouljenko, and K. G. Kousoulas, J Virol 88:5927-5935, 2014, http://dx.doi.org/10.1128/JVI.00278-14), facilitating cytoplasmic virion envelopment. Alignment of UL37 homologs encoded by alphaherpesviruses revealed the presence of highly conserved residues in the central portion of the UL37 protein. A cadre of nine UL37 site-specific mutations were produced and tested for their ability to inhibit virion envelopment and infectious virus production. Complementation analysis revealed that replacement of tyrosines 474 and 480 with alanine failed to complement the UL37-null virus, while all other mutated UL37 genes complemented the virus efficiently. The recombinant virus DC474-480 constructed with tyrosines 474, 476, 477, and 480 mutated to alanine residues produced a gK-null-like phenotype characterized by the production of very small plaques and accumulation of capsids in the cytoplasm of infected cells. Recombinant viruses having either tyrosine 476 or 477 replaced with alanine produced a wild-type phenotype. Immunoprecipitation assays revealed that replacement of all four tyrosines with alanines substantially reduced the ability of gK to interact with UL37. Alignment of HSV UL37 with the human cytomegalovirus and Epstein-Barr virus UL37 homologs revealed that Y480 was conserved only for alphaherpesviruses. Collectively, these results suggest that the UL37 conserved tyrosine 480 residue plays a crucial role in interactions with gK to facilitate cytoplasmic virion envelopment and infectious virus production.ImportanceThe HSV-1 UL37 protein is conserved among all herpesviruses, functions in both retrograde and anterograde transport of virion capsids, and plays critical roles in cytoplasmic virion envelopment by interacting with gK. We show here that UL37 tyrosine residues conserved among all alphaherpesviruses serve critical roles in cytoplasmic virion envelopment and interactions with gK.
| S-EPMC5105669 | biostudies-literature
Project description:Glycoprotein E (gE) of HSV plays a key role in cell-to-cell spread and virus-induced cell fusion. Here, we report that this function of gE requires the cooperation of tegument proteins UL11, UL16, and UL21. We found that the four proteins come together with very high efficiency to form a complex in transfected cells and in a manner that is regulated and coordinated. In particular, the inefficient interaction of UL16 with each membrane protein (UL11 and gE) observed in pairwise transfections became efficient when other binding partners were present. The significance of these interactions was revealed in studies of viral mutants, which showed that each of these tegument proteins is critical for processing, transport, and biological activity of gE. These findings provide insights into the mechanisms of how gE executes its function and also have implications in understanding HSV assembly and budding.
| S-EPMC3511771 | biostudies-literature
Project description:During herpes simplex virus 1 (HSV1) egress in neurons, viral particles travel from the neuronal cell body along the axon towards the synapse. Whether HSV1 particles are transported as enveloped virions as proposed by the 'married' model or as non-enveloped capsids suggested by the 'separate' model is controversial. Specific viral proteins may form a recruitment platform for microtubule motors that catalyze such transport. However, their subviral location has remained elusive. Here we established a system to analyze herpesvirus egress by cryo electron tomography. At 16 h post infection, we observed intra-axonal transport of progeny HSV1 viral particles in dissociated hippocampal neurons by live-cell fluorescence microscopy. Cryo electron tomography of frozen-hydrated neurons revealed that most egressing capsids were transported independently of the viral envelope. Unexpectedly, we found not only DNA-containing capsids (cytosolic C-capsids), but also capsids lacking DNA (cytosolic A-/B-capsids) in mid-axon regions. Subvolume averaging revealed lower amounts of tegument on cytosolic A-/B-capsids than on C-capsids. Nevertheless, all capsid types underwent active axonal transport. Therefore, even few tegument proteins on the capsid vertices seemed to suffice for transport. Secondary envelopment of capsids was observed at axon terminals. On their luminal face, the enveloping vesicles were studded with typical glycoprotein-like spikes. Furthermore, we noted an accretion of tegument density at the concave cytosolic face of the vesicle membrane in close proximity to the capsids. Three-dimensional analysis revealed that these assembly sites lacked cytoskeletal elements, but that filamentous actin surrounded them and formed an assembly compartment. Our data support the 'separate model' for HSV1 egress, i.e. progeny herpes viruses being transported along axons as subassemblies and not as complete virions within transport vesicles.
| S-EPMC3240593 | biostudies-literature
Project description:The predicted 80 open reading frames (ORFs) of herpes simplex virus 1 (HSV-1) have been intensively studied for decades. Here, we unravel the complete viral transcriptome and translatome during lytic infection with base-pair resolution by computational integration of multi-omics data. We identify a total of 201 transcripts and 284 ORFs including all known and 46 novel large ORFs. This includes a so far unknown ORF in the locus deleted in the FDA-approved oncolytic virus Imlygic. Multiple transcript isoforms expressed from individual gene loci explain translation of the vast majority of ORFs as well as N-terminal extensions (NTEs) and truncations. We show that NTEs with non-canonical start codons govern the subcellular protein localization and packaging of key viral regulators and structural proteins. We extend the current nomenclature to include all viral gene products and provide a genome browser that visualizes all the obtained data from whole genome to single-nucleotide resolution.
| S-EPMC7184758 | biostudies-literature