Visualization of Tegument-Capsid Interactions and DNA in Intact Herpes Simplex Virus Type 1 Virions

ABSTRACT Herpes simplex virus type 1 virions were examined by electron cryomicroscopy, allowing the three-dimensional structure of the infectious particle to be visualized for the first time. The capsid shell is identical to that of B-capsids purified from the host cell nucleus, with the exception of the penton channel, which is closed. The double-stranded DNA genome is organized as regularly spaced (∼26 Å) concentric layers inside the capsid. This pattern suggests a spool model for DNA packaging, similar to that for some bacteriophages. The bulk of the tegument is not icosahedrally ordered. However, a small portion appears as filamentous structures around the pentons, interacting extensively with the capsid. Their locations and interactions suggest possible roles for the tegument proteins in regulating DNA transport through the penton channel and binding to cellular transport proteins during viral infection.

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The Pattern of Tegument-Capsid Interaction in the Herpes Simplex Virus Type 1 Virion Is Not Influenced by the Small Hexon-Associated Protein VP26

Journal of Virology ◽

10.1128/jvi.75.23.11863-11867.2001 ◽

2001 ◽

Vol 75 (23) ◽

pp. 11863-11867 ◽

Cited By ~ 27

Author(s):

Dong-Hua Chen ◽

Joanita Jakana ◽

David McNab ◽

Joyce Mitchell ◽

Z. Hong Zhou ◽

...

Keyword(s):

Herpes Simplex Virus ◽

Herpes Simplex ◽

Virus Type ◽

Herpes Simplex Virus Type ◽

Three Dimensional ◽

Dimensional Structure ◽

Binding Properties ◽

Potential Binding ◽

Simplex Virus

ABSTRACT Examination of the three-dimensional structure of intact herpes simplex virus type 1 (HSV-1) virions had revealed that the icosahedrally symmetrical interaction between the tegument and capsid involves the pentons but not the hexons (Z. H. Zhou, D. H. Chen, J. Jakana, F. J. Rixon, and W. Chiu, J. Virol. 73:3210–3218, 1999). To account for this, we postulated that the presence of the small capsid protein, VP26, on top of the hexons was masking potential binding sites and preventing tegument attachment. We have now tested this hypothesis by determining the structure of virions lacking VP26. Apart from the obvious absence of VP26 from the capsids, the structures of the VP26 minus and wild-type virions were essentially identical. Notably, they showed the same tegument attachment patterns, thereby demonstrating that VP26 is not responsible for the divergent tegument binding properties of pentons and hexons.

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The three-dimensional structure of thymidine kinase from Herpes simplex virus type 1

FEBS Letters ◽

10.1016/0014-5793(95)00680-8 ◽

1995 ◽

Vol 368 (2) ◽

pp. 289-292 ◽

Cited By ~ 61

Author(s):

Klemens Wild ◽

Thomas Bohner ◽

André Aubry ◽

Gerd Folkers ◽

Georg E. Schulz

Keyword(s):

Herpes Simplex Virus ◽

Herpes Simplex ◽

Thymidine Kinase ◽

Virus Type ◽

Herpes Simplex Virus Type ◽

Three Dimensional ◽

Dimensional Structure ◽

Three Dimensional Structure ◽

Simplex Virus

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Evidence for Controlled Incorporation of Herpes Simplex Virus Type 1 UL26 Protease into Capsids

Journal of Virology ◽

10.1128/jvi.74.15.6838-6848.2000 ◽

2000 ◽

Vol 74 (15) ◽

pp. 6838-6848 ◽

Cited By ~ 41

Author(s):

Amy K. Sheaffer ◽

William W. Newcomb ◽

Jay C. Brown ◽

Min Gao ◽

Sandra K. Weller ◽

...

Keyword(s):

Herpes Simplex Virus ◽

Herpes Simplex ◽

Virus Type ◽

Herpes Simplex Virus Type ◽

Scaffold Proteins ◽

Wild Type ◽

Protease Domain ◽

Capsid Shell ◽

Simplex Virus

ABSTRACT Herpes simplex virus type 1 (HSV-1) capsids are initially assembled with an internal protein scaffold. The scaffold proteins, encoded by overlapping in-frame UL26 and UL26.5 transcripts, are essential for formation and efficient maturation of capsids. UL26 encodes an N-terminal protease domain, and its C-terminal oligomerization and capsid protein-binding domains are identical to those of UL26.5. The UL26 protease cleaves itself, releasing minor scaffold proteins VP24 and VP21, and the more abundant UL26.5 protein, releasing the major scaffold protein VP22a. Unlike VP21 and VP22a, which are removed from capsids upon DNA packaging, we demonstrate that VP24 (containing the protease domain) is quantitatively retained. To investigate factors controlling UL26 capsid incorporation and retention, we used a mutant virus that fails to express UL26.5 (ΔICP35 virus). Purified ΔICP35 B capsids showed altered sucrose gradient sedimentation and lacked the dense scaffold core seen in micrographs of wild-type B capsids but contained capsid shell proteins in wild-type amounts. Despite C-terminal sequence identity between UL26 and UL26.5, ΔICP35 capsids lacking UL26.5 products did not contain compensatory high levels of UL26 proteins. Therefore, HSV capsids can be maintained and/or assembled on a minimal scaffold containing only wild-type levels of UL26 proteins. In contrast to UL26.5, increased expression of UL26 did not compensate for the ΔICP35growth defect. While indirect, these findings are consistent with the view that UL26 products are restricted from occupying abundant UL26.5 binding sites within the capsid and that this restriction is not controlled by the level of UL26 protein expression. Additionally, ΔICP35 capsids contained an altered complement of DNA cleavage and packaging proteins, suggesting a previously unrecognized role for the scaffold in this process.

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pH Reduction as a Trigger for Dissociation of Herpes Simplex Virus Type 1 Scaffolds

Journal of Virology ◽

10.1128/jvi.76.15.7407-7417.2002 ◽

2002 ◽

Vol 76 (15) ◽

pp. 7407-7417 ◽

Cited By ~ 28

Author(s):

David A. McClelland ◽

James D. Aitken ◽

David Bhella ◽

David McNab ◽

Joyce Mitchell ◽

...

Keyword(s):

Herpes Simplex Virus ◽

Herpes Simplex ◽

Virus Type ◽

Herpes Simplex Virus Type ◽

Essential Feature ◽

Scaffolding Protein ◽

Capsid Shell ◽

Shell Proteins ◽

Simplex Virus

ABSTRACT Assembly of the infectious herpes simplex virus type 1 virion is a complex, multistage process that begins with the production of a procapsid, which is formed by the condensation of capsid shell proteins around an internal scaffold fashioned from multiple copies of the scaffolding protein, pre-VP22a. The ability of pre-VP22a to interact with itself is an essential feature of this process. However, this self-interaction must subsequently be reversed to allow the scaffolding proteins to exit from the capsid to make room for the viral genome to be packaged. The nature of the process by which dissociation of the scaffold is accomplished is unknown. Therefore, to investigate this process, the properties of isolated scaffold particles were investigated. Electron microscopy and gradient sedimentation studies showed that the particles could be dissociated by low concentrations of chaotropic agents and by moderate reductions in pH (from 7.2 to 5.5). Fluorescence spectroscopy and circular dichroism analyses revealed that there was relatively little change in tertiary and secondary structures under these conditions, indicating that major structural transformations are not required for the dissociation process. We suggest the possibility that dissociation of the scaffold may be triggered by a reduction in pH brought about by the entry of the viral DNA into the capsid.

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The 25 amino acid residues at the carboxy terminus of the herpes simplex virus type 1 UL26.5 protein are required for the formation of the capsid shell around the scaffold

Journal of General Virology ◽

10.1099/0022-1317-76-7-1611 ◽

1995 ◽

Vol 76 (7) ◽

pp. 1611-1621 ◽

Cited By ~ 42

Author(s):

J. Kennard ◽

F. J. Rixon ◽

I. M. McDougall ◽

J. D. Tatman ◽

V. G. Preston

Keyword(s):

Herpes Simplex Virus ◽

Amino Acid ◽

Herpes Simplex ◽

Virus Type ◽

Herpes Simplex Virus Type ◽

Amino Acid Residues ◽

Carboxy Terminus ◽

Capsid Shell ◽

Simplex Virus

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Three-Dimensional Structure of Herpes Simplex Virus Type 1 Glycoprotein D at 2.4-Nanometer Resolution

Journal of Virology ◽

10.1128/jvi.73.9.7830-7834.1999 ◽

1999 ◽

Vol 73 (9) ◽

pp. 7830-7834 ◽

Cited By ~ 2

Author(s):

Andrew Pilling ◽

Mark F. Rosenberg ◽

Sharon H. Willis ◽

Joachim Jäger ◽

Gary H. Cohen ◽

...

Keyword(s):

Herpes Simplex Virus ◽

Herpes Simplex ◽

Virus Type ◽

Herpes Simplex Virus Type ◽

Three Dimensional ◽

Virus Infectivity ◽

Glycoprotein D ◽

Virus Envelope ◽

Simplex Virus

ABSTRACT Herpes simplex virus type 1 glycoprotein D (gD) is essential for virus infectivity and is responsible for binding to cellular membrane proteins and subsequently promoting fusion between the virus envelope and the cell. No structural data are available for gD or for any other herpesvirus envelope protein. Here we present a three-dimensional model for the baculovirus-expressed truncated protein gD1(306t) based on electron microscopic data. We demonstrate that gD1(306t) appears as a homotetramer containing a pronounced pocket in the center of the molecule. Monoclonal antibody binding demonstrates that the molecule is oriented such that the pocket protrudes away from the virus envelope.

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