PREPs: herpes simplex virus type 1-specific particles produced by infected cells when viral DNA replication is blocked.

The UL15, UL28 and UL33 proteins of herpes simplex virus type 1 (HSV-1) are thought to comprise a terminase complex responsible for cleavage and packaging of the viral genome into pre-assembled capsids. Immunofluorescence studies confirmed that shortly after infection with wild-type HSV-1 these three proteins localize to viral DNA replication compartments within the nucleus, identified by the presence of the single-stranded DNA-binding protein, ICP8. In cells infected with either UL28- or UL33-null mutants, the other two terminase proteins also co-localized with ICP8. In contrast, neither UL28 nor UL33 was detectable in replication compartments following infection with a UL15-null mutant, although Western blot analysis showed they were present in normal amounts in the infected cells. Provision of UL15 in a complementing cell line restored the ability of all three proteins to localize to replication compartments. These data indicate that UL15 plays a key role in localizing the terminase complex to DNA replication compartments, and that it can interact independently with UL28 and UL33.

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Binding of the herpes simplex virus type 1 UL9 gene product to an origin of viral DNA replication

Nucleic Acids Research ◽

10.1093/nar/17.4.1409 ◽

1989 ◽

Vol 17 (4) ◽

pp. 1409-1425 ◽

Cited By ~ 32

Author(s):

Hazel M. Weir ◽

Janice M. Calder ◽

Nigel D. Stow

Keyword(s):

Herpes Simplex Virus ◽

Dna Replication ◽

Herpes Simplex ◽

Gene Product ◽

Virus Type ◽

Herpes Simplex Virus Type ◽

Viral Dna ◽

Viral Dna Replication ◽

Simplex Virus

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The Herpes Simplex Virus Type 1 Cleavage/Packaging Protein, UL32, Is Involved in Efficient Localization of Capsids to Replication Compartments

Journal of Virology ◽

10.1128/jvi.72.3.2463-2473.1998 ◽

1998 ◽

Vol 72 (3) ◽

pp. 2463-2473 ◽

Cited By ~ 92

Author(s):

Carmela Lamberti ◽

Sandra K. Weller

Keyword(s):

Herpes Simplex Virus ◽

Herpes Simplex ◽

Virus Type ◽

Herpes Simplex Virus Type ◽

Nuclear Staining ◽

Wild Type ◽

Viral Dna ◽

Infected Cells ◽

Simplex Virus

ABSTRACT Six genes, including UL32, have been implicated in the cleavage and packaging of herpesvirus DNA into preassembled capsids. We have isolated a UL32 insertion mutant which is capable of near-wild-type levels of viral DNA synthesis; however, the mutant virus is unable to cleave and package viral DNA, consistent with the phenotype of a previously isolated temperature-sensitive herpes simplex virus type 1 mutant, tsN20 (P. A. Schaffer, G. M. Aron, N. Biswal, and M. Benyesh-Melnick, Virology 52:57–71, 1973). A polyclonal antibody which recognizes UL32 was previously used by Chang et al. (Y. E. Chang, A. P. Poon, and B. Roizman, J. Virol. 70:3938–3946, 1996) to demonstrate that UL32 accumulates predominantly in the cytoplasm of infected cells. In this report, a functional epitope-tagged version of UL32 showed that while UL32 is predominantly cytoplasmic, some nuclear staining which colocalizes with the major DNA binding protein (ICP8, UL29) in replication compartments can be detected. We have also used a monoclonal antibody (5C) specific for the hexon form of major capsid protein VP5 to study the distribution of capsids during infection. In cells infected with wild-type KOS (6 and 8 h postinfection), 5C staining patterns indicate that capsids are present in nuclei within replication compartments. These results suggest that cleavage and packaging occur in replication compartments at least at 6 and 8 h postinfection. Cells infected with the UL32 mutant exhibit a hexon staining pattern which is more diffusely distributed throughout the nucleus and which is not restricted to replication compartments. We propose that UL32 may play a role in “bringing” preassembled capsids to the sites of DNA packaging and that the failure to localize to replication compartments may explain the cleavage/packaging defect exhibited by this mutant. These results suggest that the UL32 protein is required at a step distinct from those at which other cleavage and packaging proteins are required and may be involved in the correct localization of capsids within infected cells.

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Phosphorylation of the Herpes Simplex Virus Type 1 Origin Binding Protein

Journal of Virology ◽

10.1128/jvi.75.2.628-637.2001 ◽

2001 ◽

Vol 75 (2) ◽

pp. 628-637 ◽

Cited By ~ 16

Author(s):

Jennifer A. Isler ◽

Priscilla A. Schaffer

Keyword(s):

Herpes Simplex Virus ◽

Dna Replication ◽

Herpes Simplex ◽

Viral Dna ◽

Viral Dna Replication ◽

Origin Binding Protein ◽

Infected Cells ◽

Simplex Virus ◽

Replication Initiator

ABSTRACT The herpes simplex virus type 1 (HSV-1) origin binding protein (OBP), the product of the UL9 gene, is one of seven HSV-encoded proteins required for viral DNA replication. OBP performs multiple functions characteristic of a DNA replication initiator protein, including origin-specific DNA binding and ATPase and helicase activities, as well as the ability to interact with viral and cellular proteins involved in DNA replication. Replication initiator proteins in other systems, including those of other DNA viruses, are known to be regulated by phosphorylation; however, the role of phosphorylation in OBP function has been difficult to assess due to the low level of OBP expression in HSV-infected cells. Using a metabolic labeling and immunoprecipitation approach, we obtained evidence that OBP is phosphorylated during HSV-1 infection. Kinetic analysis of metabolically labeled cells indicated that the levels of OBP expression and phosphorylation increased at approximately 4 h postinfection. Notably, when expressed from a transfected plasmid, a recombinant baculovirus, or a recombinant adenovirus (AdOBP), OBP was phosphorylated minimally, if at all. In contrast, superinfection of AdOBP-infected cells with an OBP-null mutant virus increased the level of OBP phosphorylation approximately threefold, suggesting that HSV-encoded viral or HSV-induced cellular factors enhance the level of OBP phosphorylation. Using HSV mutants inhibited at sequential stages of the viral life cycle, we demonstrated that this increase in OBP phosphorylation is dependent on early protein synthesis and is independent of viral DNA replication. Based on gel mobility shift assays, phosphorylation does not appear to affect the ability of OBP to bind to the HSV origins.

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Characterization of nuclear structures in cells infected with herpes simplex virus type 1 in the absence of viral DNA replication.

Journal of Virology ◽

10.1128/jvi.70.3.1751-1758.1996 ◽

1996 ◽

Vol 70 (3) ◽

pp. 1751-1758 ◽

Cited By ~ 44

Author(s):

C J Lukonis ◽

S K Weller

Keyword(s):

Herpes Simplex Virus ◽

Dna Replication ◽

Herpes Simplex ◽

Herpes Simplex Virus Type ◽

Viral Dna ◽

Viral Dna Replication ◽

Nuclear Structures ◽

Simplex Virus

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Binding of surfactant protein A (SP-A) to herpes simplex virus type 1-infected cells is mediated by the carbohydrate moiety of SP-A.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)74002-2 ◽

1992 ◽

Vol 267 (35) ◽

pp. 25039-25043 ◽

Cited By ~ 1

Author(s):

J.F. van Iwaarden ◽

J.A. van Strijp ◽

H Visser ◽

H.P. Haagsman ◽

J Verhoef ◽

...

Keyword(s):

Herpes Simplex Virus ◽

Herpes Simplex ◽

Virus Type ◽

Herpes Simplex Virus Type ◽

Protein A ◽

Surfactant Protein ◽

Surfactant Protein A ◽

Infected Cells ◽

Simplex Virus

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Nucleolin Is Required for Efficient Nuclear Egress of Herpes Simplex Virus Type 1 Nucleocapsids

Journal of Virology ◽

10.1128/jvi.02007-09 ◽

2009 ◽

Vol 84 (4) ◽

pp. 2110-2121 ◽

Cited By ~ 29

Author(s):

Ken Sagou ◽

Masashi Uema ◽

Yasushi Kawaguchi

Keyword(s):

Herpes Simplex Virus ◽

Herpes Simplex ◽

Nuclear Membrane ◽

Herpes Simplex Virus Type ◽

Viral Dna ◽

Nuclear Egress ◽

Infected Cells ◽

Simplex Virus ◽

Hsv 1

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.

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