Phenylalanine Residues at the Carboxyl Terminus of the Herpes Simplex Virus 1 UL20 Membrane Protein Regulate Cytoplasmic Virion Envelopment and Infectious Virus Production

Charles, Anu-Susan; Chouljenko, Vladimir N.; Jambunathan, Nithya; Subramanian, R.; Mottram, Peter; Kousoulas, Konstantin G.

doi:10.1128/jvi.00657-14

Cited by 9 publications

(5 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The intra- and extracellular titers of HSV1(17 + )Lox-ΔUL20 and -CheVP26-ΔUL20 were about 1,000-fold lower than their parental strains in non-complementing Vero cells, but higher in a pUL20 complementing cell line ( S2C and S2D Fig ). Similar results have been reported for HSV1-ΔUL20 mutants in other genetic backgrounds [ 25 , 26 , 54 – 56 ]. There were little differences between the parental Lox and the -CheVP26 strains, indicating that tagging VP26 with mCherry (Che) did not impair HSV-1 replication, as reported before [ 24 , 57 ].…”

Section: Resultssupporting

confidence: 89%

Inner tegument proteins of Herpes Simplex Virus are sufficient for intracellular capsid motility in neurons but not for axonal targeting

et al. 2017

View full text Add to dashboard Cite

Upon reactivation from latency and during lytic infections in neurons, alphaherpesviruses assemble cytosolic capsids, capsids associated with enveloping membranes, and transport vesicles harboring fully enveloped capsids. It is debated whether capsid envelopment of herpes simplex virus (HSV) is completed in the soma prior to axonal targeting or later, and whether the mechanisms are the same in neurons derived from embryos or from adult hosts. We used HSV mutants impaired in capsid envelopment to test whether the inner tegument proteins pUL36 or pUL37 necessary for microtubule-mediated capsid transport were sufficient for axonal capsid targeting in neurons derived from the dorsal root ganglia of adult mice. Such neurons were infected with HSV1-ΔUL20 whose capsids recruited pUL36 and pUL37, with HSV1-ΔUL37 whose capsids associate only with pUL36, or with HSV1-ΔUL36 that assembles capsids lacking both proteins. While capsids of HSV1-ΔUL20 were actively transported along microtubules in epithelial cells and in the somata of neurons, those of HSV1-ΔUL36 and -ΔUL37 could only diffuse in the cytoplasm. Employing a novel image analysis algorithm to quantify capsid targeting to axons, we show that only a few capsids of HSV1-ΔUL20 entered axons, while vesicles transporting gD utilized axonal transport efficiently and independently of pUL36, pUL37, or pUL20. Our data indicate that capsid motility in the somata of neurons mediated by pUL36 and pUL37 does not suffice for targeting capsids to axons, and suggest that capsid envelopment needs to be completed in the soma prior to targeting of herpes simplex virus to the axons, and to spreading from neurons to neighboring cells.

show abstract

Section: Resultssupporting

confidence: 89%

Inner tegument proteins of Herpes Simplex Virus are sufficient for intracellular capsid motility in neurons but not for axonal targeting

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Firstly, we found that both ORF7 and ORF53 co-localized well with the TGN46 protein ( Figure 3A and 3B), which is widely used as a TGN marker in numerous studies (Barr et al, 2010;Donsante et al, 2011;Zhao et al, 2012;Charles et al, 2014;Nonnenmacher et al, 2015;Pillay et al, 2016). The Pearson's coefficients were 0.70 ± 0.09 and 0.68 ± 0.08 in the co-localized volume of TGN46 with ORF7 and ORF53, respectively (n = 10 in each group).…”

Section: Orf7 Co-localizes With Orf53 In the Tgn Of Infected Cellsmentioning

confidence: 79%

Varicella-zoster virus ORF7 interacts with ORF53 and plays a role in its trans-Golgi network localization

Wang

Pan

et al. 2017

Virol. Sin.

View full text Add to dashboard Cite

Varicella-zoster virus (VZV) is a neurotropic alphaherpesvirus that causes chickenpox andshingles. ORF7 is an important virulence determinant of VZV in both human skin and nerve tissues, however, its specific function and involved molecular mechanism in VZV pathogenesis remain largely elusive. Previous yeast two-hybrid studies on intraviral protein-protein interaction network in herpesviruses have revealed that VZV ORF7 may interact with ORF53, which is a virtually unstudied but essential viral protein. The aim of this study is to identify and characterize VZV ORF53, and to investigate its relationship with ORF7. For this purpose, we prepared monoclonal antibodies against ORF53 and, for the first time, characterized it as a ~40 kDa viral protein predominantly localizing to the trans-Golgi network of the infected host cell. Next, we further confirmed the interaction between ORF7 and ORF53 by co-immunoprecipitation and co-localization studies in both plasmid-transfected and VZV-infected cells. Moreover, interestingly, we found that ORF53 lost its trans-Golgi network localization and became dispersed in the cytoplasm of host cells infected with an ORF7-deleted recombinant VZV, and thus ORF7 seems to play a role in normal subcellular localization of ORF53. Collectively, these results suggested that ORF7 and ORF53 may function as a complex during infection, which may be implicated in VZV pathogenesis. KEYWORDSvaricella-zoster virus (VZV); ORF7; ORF53; protein-protein interaction; trans-Golgi network

show abstract

“…To assess the requirement of UL21 for these Syn mutants, we chose two syncytial mutations for each locus to test whether the absence of UL21 leads to a loss of fusion. For UL20, we used the syncytial substitutions R209A (37) and F222A (38), as these have been described as ones that are not associated with loss of viral titer in an otherwise wild-type background. For UL24, the syncytial substitutions were the E99A/K101A combination of changes and the singular point mutation G121A (39).…”

Section: Fig 2 Legend (Continued)mentioning

confidence: 99%

The UL21 Tegument Protein of Herpes Simplex Virus 1 Is Differentially Required for the Syncytial Phenotype

Sarfo

Starkey

Mellinger

et al. 2017

J Virol

View full text Add to dashboard Cite

The initial goal of this study was to reexamine the requirement of UL21 for herpes simplex virus 1 (HSV-1) replication. Previous studies suggested that UL21 is dispensable for replication in cell cultures, but a recent report on HSV-2 challenges those findings. As was done for the HSV-2 study, a UL21-null virus was made and propagated on complementing cells to discourage selection of compensating mutations. This HSV-1 mutant was able to replicate in noncomplementing cells, even at a low multiplicity of infection (MOI), though a reduction in titer was observed. Also, increased proportions of empty capsids were observed in the cytoplasm, suggesting a role for UL21 in preventing their exit from the nucleus. Surprisingly, passage of the null mutant resulted in rapid outgrowth of syncytial (Syn) variants. This was unexpected because UL21 has been shown to be required for the Syn phenotype. However, earlier experiments made use of only the A855V syncytial mutant of glycoprotein B (gB), and the Syn phenotype can also be produced by substitutions in glycoprotein K (gK), UL20, and UL24. Sequencing of the syncytial variants revealed mutations in the gK locus, but UL21 was shown to be dispensable for UL20 and UL24 To test whether UL21 is needed only for the A855V mutant, additional gB derivatives were examined in the context of the null virus, and all produced lytic rather than syncytial sites of infection. Thus, UL21 is required only for the gB phenotype. This is the first example of a differential requirement for a viral protein across the four loci. UL21 is conserved among alphaherpesviruses, but its role is poorly understood. This study shows that HSV-1 can replicate without UL21, although the virus titers are greatly reduced. The null virus had greater proportions of empty (DNA-less) capsids in the cytoplasm of infected cells, suggesting that UL21 may play a role in retaining them in the nucleus. This is consistent with reports showing UL21 to be capsid associated and localized to the nuclei of infected cells. UL21 also appears to be needed for viral membrane activities. It was found to be required for virus-mediated cell fusion, but only for mutants that harbor syncytial mutations in gB (not variants of gK, UL20, or UL24). The machinery needed for syncytial formation is similar to that needed for direct spread of the virus through cell junctions, and these studies show that UL21 is required for cell-to-cell spread even in the absence of syncytial mutations.

show abstract

Phenylalanine Residues at the Carboxyl Terminus of the Herpes Simplex Virus 1 UL20 Membrane Protein Regulate Cytoplasmic Virion Envelopment and Infectious Virus Production

Cited by 9 publications

References 45 publications

Inner tegument proteins of Herpes Simplex Virus are sufficient for intracellular capsid motility in neurons but not for axonal targeting

Inner tegument proteins of Herpes Simplex Virus are sufficient for intracellular capsid motility in neurons but not for axonal targeting

Varicella-zoster virus ORF7 interacts with ORF53 and plays a role in its trans-Golgi network localization

The UL21 Tegument Protein of Herpes Simplex Virus 1 Is Differentially Required for the Syncytial Phenotype

Contact Info

Product

Resources

About