Role of HSV-1 Capsid Vertex-Specific Component (CVSC) and Viral Terminal DNA in Capsid Docking at the Nuclear Pore.

José Ramon Villanueva-Valencia,Alex Evilevitch,Efthymios Tsimtsirakis

doi:10.3390/v13122515

José Ramon Villanueva-Valencia, Alex Evilevitch + Show 1 more

Open Access

https://doi.org/10.3390/v13122515

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Journal: Viruses	Publication Date: Dec 15, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: Lund University

Abstract

Penetration of the viral genome into a host cell nucleus is critical for initiation of viral replication for most DNA viruses and a few RNA viruses. For herpesviruses, viral DNA ejection into a nucleus occurs when the capsid docks at the nuclear pore complex (NPC) basket with the correct orientation of the unique capsid portal vertex. It has been shown that capsid vertex-specific component (CVSC) proteins, which are located at the twelve vertices of the human herpes simplex virus type 1 (HSV-1) capsid, interact with nucleoporins (Nups) of NPCs. However, it remained unclear whether CVSC proteins determine capsid-to-NPC binding. Furthermore, it has been speculated that terminal DNA adjacent to the portal complex of DNA-filled C-capsids forms a structural motif with the portal cap (which retains DNA in the capsid), which mediates capsid-NPC binding. We demonstrate that terminal viral DNA adjacent to the portal proteins does not present a structural element required for capsid-NPC binding. Our data also show that level of CVSC proteins on the HSV-1 capsid affects level of NPC binding. To elucidate the capsid-binding process, we use an isolated, reconstituted cell nucleus system that recapitulates capsid-nucleus binding in vivo without interference from trafficking kinetics of capsids moving toward the nucleus. This allows binding of non-infectious capsid maturation intermediates with varying levels of vertex-specific components. This experimental system provides a platform for investigating virus–host interaction at the nuclear membrane.

Highlights

For most DNA viruses and a few RNA viruses, the central virus–host interface during the course of infection is the nuclear membrane, which controls the penetration of viral genome into the host nucleus, subsequently leading to infection [1,2,3]
We explore the role of capsid surface structural motifs in docking to nuclear pore complex (NPC), the key step required for ejection of viral genome into a host nucleus
We investigate the role of capsid vertex-specific component (CVSC) proteins, which are located at the twelve vertices of the herpes simplex virus type 1 (HSV-1) capsid and have been found to interact with nucleoporins (Nups) of NPCs [9,10,11], in mediating capsid docking to the NPCs

Summary

Introduction

For most DNA viruses and a few RNA viruses, the central virus–host interface during the course of infection is the nuclear membrane, which controls the penetration of viral genome into the host nucleus, subsequently leading to infection [1,2,3]. Despite virus–NPC binding being a significant part of the viral infectious cycle, the molecular details of this interaction are poorly understood for most viruses, including herpesviruses. We explore the role of capsid surface structural motifs in docking to NPCs, the key step required for ejection of viral genome into a host nucleus. We answer a long-standing question of whether the terminal part of the viral encapsidated DNA that is adjacent to the portal is required as a structural element for NPC docking [5,6,7,8]. We investigate the role of capsid vertex-specific component (CVSC) proteins, which are located at the twelve vertices of the HSV-1 capsid and have been found to interact with nucleoporins (Nups) of NPCs [9,10,11], in mediating capsid docking to the NPCs

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