Involvement of the Portal at an Early Step in Herpes Simplex Virus Capsid Assembly

Newcomb, William W.; Homa, Fred L.; Brown, Jay C.

doi:10.1128/jvi.79.16.10540-10546.2005

Cited by 68 publications

(82 citation statements)

References 35 publications

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“…Procapsids can assemble in the absence of UL6 via an interaction between UL26.5 and VP5 (27); however, when UL6 is present at the initiation of assembly, UL6-containing capsids are formed, suggesting that the portal is incorporated at a very early step in assembly (26). These results also suggest that capsid assembly is regulated such that capsids lacking UL6 do not assemble efficiently in infected cells.…”

supporting

confidence: 55%

“…The UL6 protein plays multiple roles during viral assembly and encapsidation, including ring formation, interaction with scaffold and VP5 to nucleate the assembly of the procapsid shell, the docking of the terminase, and acting as a conduit for the uptake of viral DNA into capsids (8,9,20,25,26,28,31,32,40,42,46). It also is likely that the UL6 portal plays a role during subsequent infections.…”

Section: Resultsmentioning

confidence: 99%

“…UL6 becomes incorporated into nascent HSV-1 capsids mediated by interaction with the UL26.5 major scaffold protein (15,26,29,35). Procapsids can assemble in the absence of UL6 via an interaction between UL26.5 and VP5 (27); however, when UL6 is present at the initiation of assembly, UL6-containing capsids are formed, suggesting that the portal is incorporated at a very early step in assembly (26).…”

mentioning

confidence: 99%

“…During HSV genome encapsidation, the portal ring provides a docking site for the terminase, an ATPdriven molecular motor that facilitates the uptake of viral DNA (34,42,45,46). Terminase is responsible not only for viral DNA uptake but also for the specific cleavage of viral genomes such that a monomeric unit of viral DNA is packaged in each capsid (1,4,18,19,33,42,44,46,47).UL6 becomes incorporated into nascent HSV-1 capsids mediated by interaction with the UL26.5 major scaffold protein (15,26,29,35). Procapsids can assemble in the absence of UL6 via an interaction between UL26.5 and VP5 (27); however, when UL6 is present at the initiation of assembly, UL6-containing capsids are formed, suggesting that the portal is incorporated at a very early step in assembly (26).…”

mentioning

confidence: 99%

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Disulfide Bond Formation in the Herpes Simplex Virus 1 UL6 Protein Is Required for Portal Ring Formation and Genome Encapsidation

Albright

Nellissery

Szczepaniak

et al. 2011

J Virol

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The herpes simplex virus 1 (HSV-1) UL6 portal protein forms a 12-subunit ring structure at a unique capsid vertex which functions as a conduit for the encapsidation of the viral genome. We have demonstrated previously that the leucine zipper region of UL6 is important for intersubunit interactions and stable ring formation (J. K. Nellissery, R. Szczepaniak, C. Lamberti, and S. K. Weller, J. Virol. 81:8868-8877, 2007). We now demonstrate that intersubunit disulfide bonds exist between monomeric subunits and contribute to portal ring formation and/or stability. Intersubunit disulfide bonds were detected in purified portal rings by SDS-PAGE under nonreducing conditions. Furthermore, the treatment of purified portal rings with dithiothreitol (DTT) resulted in the disruption of the rings, suggesting that disulfide bonds confer stability to this complex structure. The UL6 protein contains nine cysteines that were individually mutated to alanine. Two of these mutants, C166A and C254A, failed to complement a UL6 null mutant in a transient complementation assay. Furthermore, viral mutants bearing the C166A and C254A mutations failed to produce infectious progeny and were unable to cleave or package viral DNA. In cells infected with C166A or C254A, B capsids were produced which contained UL6 at reduced levels compared to those seen in wild-type capsids. In addition, C166A and C254A mutant proteins expressed in insect cells infected with recombinant baculovirus failed to form ring structures. Cysteines at positions 166 and 254 thus appear to be required for intersubunit disulfide bond formation. Taken together, these results indicate that disulfide bond formation is required for portal ring formation and/or stability and for the production of procapsids that are capable of encapsidation.The products of herpes simplex virus 1 (HSV-1) DNA replication are head-to-tail concatemers which are resolved into monomeric genomic units and packaged into a preformed capsid shell in the nucleus of the infected cell (reviewed in references 2, 6, and 10). The HSV-1 capsid shell is composed of the major capsid protein (VP5), two triplex proteins (VP19C and VP23), and VP26. Minor capsid proteins include UL6, UL15, UL17, UL25, UL28, and UL33. The process of cleavage and DNA packaging requires the six minor capsid proteins as well as UL32, which is not found associated with capsids (2, 6, 10, 21).HSV capsid formation and genome encapsidation are reminiscent of the double-stranded DNA bacteriophages, in that a procapsid shell is preassembled around a scaffolding protein that is not present in the mature virion (3, 37, 38). Bacteriophage and herpesviruses share an important structural element, a dodecameric portal ring located at a unique capsid vertex (8,9,28,40). During HSV genome encapsidation, the portal ring provides a docking site for the terminase, an ATPdriven molecular motor that facilitates the uptake of viral DNA (34,42,45,46). Terminase is responsible not only for viral DNA uptake but also for the specific cleavage of viral genomes ...

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supporting

confidence: 55%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Disulfide Bond Formation in the Herpes Simplex Virus 1 UL6 Protein Is Required for Portal Ring Formation and Genome Encapsidation

Albright

Nellissery

Szczepaniak

et al. 2011

J Virol

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“…In addition to the terminase, the other critical packaging component is the portal protein. With bacteriophages and herpes simplex virus (HSV) type-1, the portal protein forms a homo-multimeric complex that serves as a channel for translocation of the DNA into the capsid (Valpuesta & Carrascosa, 1994;Newcomb et al, 2001Newcomb et al, , 2005. In addition to this, the portal plays a fundamental role in the assembly of capsids.…”

mentioning

confidence: 99%

Assembly of monomeric human cytomegalovirus pUL104 into portal structures

Holzenburg

Dittmer

Bogner

2009

Journal of General Virology

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In order for human cytomegalovirus (HCMV) to replicate, concatemeric DNA has to be cleaved into unit-length genomes and packaged into preformed capsids. For packaging to take place and DNA to be translocated, a channel is required in the capsid. Viral capsid channels are generally formed by portal proteins. Here, we show by cross-linking, native gel electrophoresis of infected cells and gel permeation chromatography that the HCMV portal candidate protein pUL104 can form dimers and higher order multimers. Electron microscopy of purified monomeric pUL104 after 5 min incubation revealed that the protein had assembled into a multimeric form and that this form closely resembles complete portal assembly. This is the first study to show that pUL104 monomers have the ability to form portal complexes without additional viral proteins.The maturation of herpesviruses, as well as doublestranded DNA (dsDNA) bacteriophages, is the first step in the viral life cycle and harbours a number of common features. Starting with the assembly of the viral procapsid, subsequent DNA replication leads to concatenated DNA that is cleaved into unit-length genomes and packaged into the preformed capsids (Adelman et al., 2001;Black, 1989;Bogner, 2002;Catalano, 2000). Packaging is an energyconsumptive mechanism and with bacteriophages it was demonstrated that one molecule of ATP is required to package 2 bp of DNA (Guo et al., 1987;Morita et al., 1993). The viral nanomotor, which is involved in this process, is composed of the terminase and the portal. The human cytomegalovirus (HCMV) terminase consists of a large and a small subunit, called viral protein pUL56 and pUL89, respectively. The large subunit endows the terminase with ATPase activity and the small subunit is required for cleavage of concatemeric DNA (Bogner, 2002;Hwang & Bogner, 2002;Scheffczik et al., 2002;Scholz et al., 2003). In addition to the terminase, the other critical packaging component is the portal protein. With bacteriophages and herpes simplex virus (HSV) type-1, the portal protein forms a homo-multimeric complex that serves as a channel for translocation of the DNA into the capsid (Valpuesta & Carrascosa, 1994;Newcomb et al., 2001Newcomb et al., , 2005. In addition to this, the portal plays a fundamental role in the assembly of capsids. Even though the portal proteins known so far share no sequence homology, the architecture of the portals is strikingly similar. All portal proteins occupy one vertex location in the capsid and are thought to be dodecamers upon integration (Guasch et al., 2002; Lurz et al., 2001;Trus et al., 2004;Valpuesta & Carrascosa, 1994); they are typically composed of a crown, a stalk and a wing domain. The crown and the stalk delineate a narrow central channel between which the wider wing domain is located (Agirrezabala et al., 2005;Poliakov et al., 2007).With HCMV, previous studies have suggested that the open reading frame UL104 encodes the portal protein . In vivo, pUL104 directly interacts with the large terminase subunit pUL56, which was sho...

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Monosynaptic restriction of the anterograde herpes simplex virus strain H129 for neural circuit tracing

Fischer

Collins

Pang

et al. 2023

J of Comparative Neurology

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Identification of synaptic partners is a fundamental task for systems neuroscience.To date, few reliable techniques exist for whole brain labeling of downstream synaptic partners in a cell-type-dependent and monosynaptic manner. Herein, we describe a novel monosynaptic anterograde tracing system based on the deletion of the gene UL6 from the genome of a cre-dependent version of the anterograde Herpes Simplex Virus 1 strain H129. Given that this knockout blocks viral genome packaging and thus viral spread, we reasoned that co-infection of a HSV H129 ΔUL6 virus with a recombinant adeno-associated virus expressing UL6 in a cre-dependent manner would result in monosynaptic spread from target cre-expressing neuronal populations. Application of this system to five nonreciprocal neural circuits resulted in labeling of neurons in expected projection areas. While some caveats may preclude certain applications, this system provides a reliable method to label postsynaptic partners in a brain-wide fashion.

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Involvement of the Portal at an Early Step in Herpes Simplex Virus Capsid Assembly

Cited by 68 publications

References 35 publications

Disulfide Bond Formation in the Herpes Simplex Virus 1 UL6 Protein Is Required for Portal Ring Formation and Genome Encapsidation

Disulfide Bond Formation in the Herpes Simplex Virus 1 UL6 Protein Is Required for Portal Ring Formation and Genome Encapsidation

Assembly of monomeric human cytomegalovirus pUL104 into portal structures

Monosynaptic restriction of the anterograde herpes simplex virus strain H129 for neural circuit tracing

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