scholarly journals Autophagic degradation of lamins facilitates the nuclear egress of herpes simplex virus type 1

2018 ◽  
Vol 218 (2) ◽  
pp. 508-523 ◽  
Author(s):  
Aykut Turan ◽  
Linda Grosche ◽  
Adalbert Krawczyk ◽  
Petra Mühl-Zürbes ◽  
Christina Drassner ◽  
...  

Dendritic cells (DCs) are crucial for the induction of potent antiviral immune responses. In contrast to immature DCs (iDCs), mature DCs (mDCs) are not permissive for infection with herpes simplex virus type 1 (HSV-1). Here, we demonstrate that HSV-1 infection of iDCs and mDCs induces autophagy, which promotes the degradation of lamin A/C, B1, and B2 in iDCs only. This in turn facilitates the nuclear egress of progeny viral capsids and thus the formation of new infectious particles. In contrast, lamin protein levels remain stable in HSV-1–infected mDCs due to an inefficient autophagic flux. Elevated protein levels of KIF1B and KIF2A in mDCs inhibited lamin degradation, likely by hampering autophagosome–lysosome fusion. Therefore, in mDCs, fewer progeny capsids were released from the nuclei into the cytosol, and fewer infectious virions were assembled. We hypothesize that inhibition of autophagic lamin degradation in mDCs represents a very powerful cellular counterstrike to inhibit the production of progeny virus and thus viral spread.

2011 ◽  
Vol 92 (12) ◽  
pp. 2734-2745 ◽  
Author(s):  
Melanie Ott ◽  
Georg Tascher ◽  
Sarah Haßdenteufel ◽  
Richard Zimmermann ◽  
Jürgen Haas ◽  
...  

Release of herpes simplex virus type 1 (HSV-1) nucleocapsids from the host nucleus relies on the nuclear egress complex consisting of the two essential proteins pUL34 and pUL31. The cytoplasmically exposed N-terminal region of pUL34 interacts with pUL31, while a hydrophobic region followed by a short luminal part mediates membrane association. Based on its domain organization, pUL34 was postulated to be a tail-anchor (TA) protein. We performed a coupled in vitro transcription/translation assay to show that membrane insertion of pUL34 occurs post-translationally. Transient transfection and localization experiments in mammalian cells were combined with HSV-1 bacterial artificial chromosome mutagenesis to reveal the functional properties of the essential pUL34 TA. Our data show that a minimal tail length of 15 residues is sufficient for nuclear envelope targeting and pUL34 function. Permutations of the pUL34 TA with orthologous regions of human cytomegalovirus pUL50 or Epstein–Barr virus pBFRF1 as well as the heterologous HSV-1 TA proteins pUL56 or pUS9 or the cellular TA proteins Bcl-2 and Vamp2 revealed that nuclear egress tolerates TAs varying in sequence and hydrophobicity, while a non-α-helical membrane anchor failed to complement the pUL34 function. In conclusion, this study provides the first mechanistic insights into the particular role of the TA of pUL34 in membrane curving and capsid egress from the host nucleus.


2006 ◽  
Vol 80 (19) ◽  
pp. 9741-9753 ◽  
Author(s):  
Gaudeline Rémillard-Labrosse ◽  
Ginette Guay ◽  
Roger Lippé

ABSTRACT Newly assembled herpesvirus capsids travel from the nucleus to the plasma membrane by a mechanism that is poorly understood. Furthermore, the contribution of cellular proteins to this egress has yet to be clarified. To address these issues, an in vitro nuclear egress assay that reproduces the exit of herpes simplex virus type 1 (HSV-1) capsids from nuclei isolated from infected cells was established. As expected, the assay has all the hallmarks of intracellular transport assays, namely, a dependence on time, energy, and temperature. Surprisingly, it is also dependent on cytosol and was slightly enhanced by infected cytosol, suggesting an implication of both host and viral proteins in the process. The capsids escaped these nuclei by budding through the inner nuclear membrane, accumulated as enveloped capsids between the two nuclear membranes, and were released in cytosol exclusively as naked capsids, exactly as in intact cells. This is most consistent with the view that the virus escapes by crossing the two nuclear membranes rather than through nuclear pores. Unexpectedly, nuclei isolated at the nonpermissive temperature from cells infected with a UL26 thermosensitive protease mutant (V701) supported capsid egress. Although electron microscopy, biochemical, and PCR analyses hinted at a likely reconstitution of capsid maturation, DNA encapsidation could not be confirmed by a traditional SQ test. This assay should prove very useful for identification of the molecular players involved in HSV-1 nuclear egress.


Cells ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 120 ◽  
Author(s):  
Natalia Saiz-Ros ◽  
Rafal Czapiewski ◽  
Ilaria Epifano ◽  
Andrew Stevenson ◽  
Selene Swanson ◽  
...  

The primary envelopment/de-envelopment of Herpes viruses during nuclear exit is poorly understood. In Herpes simplex virus type-1 (HSV-1), proteins pUL31 and pUL34 are critical, while pUS3 and some others contribute; however, efficient membrane fusion may require additional host proteins. We postulated that vesicle fusion proteins present in the nuclear envelope might facilitate primary envelopment and/or de-envelopment fusion with the outer nuclear membrane. Indeed, a subpopulation of vesicle-associated membrane protein-associated protein B (VAPB), a known vesicle trafficking protein, was present in the nuclear membrane co-locating with pUL34. VAPB knockdown significantly reduced both cell-associated and supernatant virus titers. Moreover, VAPB depletion reduced cytoplasmic accumulation of virus particles and increased levels of nuclear encapsidated viral DNA. These results suggest that VAPB is an important player in the exit of primary enveloped HSV-1 virions from the nucleus. Importantly, VAPB knockdown did not alter pUL34, calnexin or GM-130 localization during infection, arguing against an indirect effect of VAPB on cellular vesicles and trafficking. Immunogold-labelling electron microscopy confirmed VAPB presence in nuclear membranes and moreover associated with primary enveloped HSV-1 particles. These data suggest that VAPB could be a cellular component of a complex that facilitates UL31/UL34/US3-mediated HSV-1 nuclear egress.


2002 ◽  
Vol 76 (18) ◽  
pp. 9232-9241 ◽  
Author(s):  
John M. Lubinski ◽  
Ming Jiang ◽  
Lauren Hook ◽  
Yueh Chang ◽  
Chad Sarver ◽  
...  

ABSTRACT Herpes simplex virus type 1 (HSV-1) encodes a complement-interacting glycoprotein, gC, and an immunoglobulin G (IgG) Fc binding glycoprotein, gE, that mediate immune evasion by affecting multiple aspects of innate and acquired immunity, including interfering with complement components C1q, C3, C5, and properdin and blocking antibody-dependent cellular cytotoxicity. Previous studies evaluated the individual contributions of gC and gE to immune evasion. Experiments in a murine model that examines the combined effects of gC and gE immune evasion on pathogenesis are now reported. Virulence of wild-type HSV-1 is compared with mutant viruses defective in gC-mediated C3 binding, gE-mediated IgG Fc binding, or both immune evasion activities. Eliminating both activities greatly increased susceptibility of HSV-1 to antibody and complement neutralization in vitro and markedly reduced virulence in vivo as measured by disease scores, virus titers, and mortality. Studies with C3 knockout mice indicated that other activities attributed to these glycoproteins, such as gC-mediated virus attachment to heparan sulfate or gE-mediated cell-to-cell spread, do not account for the reduced virulence of mutant viruses. The results support the importance of gC and gE immune evasion in vivo and suggest potential new targets for prevention and treatment of HSV disease.


2009 ◽  
Vol 84 (4) ◽  
pp. 2110-2121 ◽  
Author(s):  
Ken Sagou ◽  
Masashi Uema ◽  
Yasushi Kawaguchi

ABSTRACT Herpesvirus nucleocapsids assemble in the nucleus and must cross the nuclear membrane for final assembly and maturation to form infectious progeny virions in the cytoplasm. It has been proposed that nucleocapsids enter the perinuclear space by budding through the inner nuclear membrane, and these enveloped nucleocapsids then fuse with the outer nuclear membrane to enter the cytoplasm. Little is known about the mechanism(s) for nuclear egress of herpesvirus nucleocapsids and, in particular, which, if any, cellular proteins are involved in the nuclear egress pathway. UL12 is an alkaline nuclease encoded by herpes simplex virus type 1 (HSV-1) and has been suggested to be involved in viral DNA maturation and nuclear egress of nucleocapsids. Using a live-cell imaging system to study cells infected by a recombinant HSV-1 expressing UL12 fused to a fluorescent protein, we observed the previously unreported nucleolar localization of UL12 in live infected cells and, using coimmunoprecipitation analyses, showed that UL12 formed a complex with nucleolin, a nucleolus marker, in infected cells. Knockdown of nucleolin in HSV-1-infected cells reduced capsid accumulation, as well as the amount of viral DNA resistant to staphylococcal nuclease in the cytoplasm, which represented encapsidated viral DNA, but had little effect on these viral components in the nucleus. These results indicated that nucleolin is a cellular factor required for efficient nuclear egress of HSV-1 nucleocapsids in infected cells.


2004 ◽  
Vol 78 (9) ◽  
pp. 4599-4608 ◽  
Author(s):  
Nina Bacher Reuven ◽  
Susumu Antoku ◽  
Sandra K. Weller

ABSTRACT The herpes simplex virus type 1 (HSV-1) alkaline nuclease, encoded by the UL12 gene, plays an important role in HSV-1 replication, as a null mutant of UL12 displays a severe growth defect. Although the precise in vivo role of UL12 has not yet been determined, several in vitro activities have been identified for the protein, including endo- and exonuclease activities, interaction with the HSV-1 single-stranded DNA binding protein ICP8, and an ability to promote strand exchange in conjunction with ICP8. In this study, we examined a naturally occurring N-terminally truncated version of UL12 called UL12.5. Previous studies showing that UL12.5 exhibits nuclease activity but is unable to complement a UL12 null virus posed a dilemma and suggested that UL12.5 may lack a critical activity possessed by the full-length protein, UL12. We constructed a recombinant baculovirus capable of expressing UL12.5 and purified soluble UL12.5 from infected insect cells. The purified UL12.5 exhibited both endo- and exonuclease activities but was less active than UL12. Like UL12, UL12.5 could mediate strand exchange with ICP8 and could also be coimmunoprecipitated with ICP8. The primary difference between the two proteins was in their intracellular localization, with UL12 localizing to the nucleus and UL12.5 remaining in the cytoplasm. We mapped a nuclear localization signal to the N terminus of UL12, the domain absent from UL12.5. In addition, when UL12.5 was overexpressed so that some of the enzyme leaked into the nucleus, it was able to partially complement the UL12 null mutant.


2003 ◽  
Vol 77 (5) ◽  
pp. 3307-3311 ◽  
Author(s):  
Sarah M. Richart ◽  
Scott A. Simpson ◽  
Claude Krummenacher ◽  
J. Charles Whitbeck ◽  
Lewis I. Pizer ◽  
...  

ABSTRACT Primary cultures of rat and mouse sensory neurons were used to study the entry of herpes simplex virus type 1 (HSV-1). Soluble, truncated nectin-1 but not HveA prevented viral entry. Antibodies against nectin-1 also blocked infection of rat neurons. These results indicate that nectin-1 is the primary receptor for HSV-1 infection of sensory neurons.


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