Regulation of the initial stages of herpes simplex virus lytic infection and reactivation from latency

Lead Research Organisation: MRC Virology Unit

Abstract

Herpes simplex virus type 1 (HSV-1) is one of several herpesviruses that infect a high proportion of the human population. Although these viruses do not generally cause dangerous diseases, herpesvirus infections can become serious or even fatal in the newborn and those with damaged immune systems. Genital herpes simplex virus infections are one of the most common sexually transmitted diseases. Herpesviruses are common because after an initial infection they attain a latent state and are carried by the individual for life. As there are no treatments to eradicate latent virus, an understanding of how herpesviruses attain, maintain and reactivate from latency is necessary for improved treatments for herpesvirus diseases. Current research aims to elucidate the molecular mechanisms by which lytic and latent HSV-1 infection are regulated. HSV-1 encodes regulatory proteins that interact with cellular proteins and control systems, either interfering with or hijacking them to serve the needs of the virus. An understanding of these processes will reveal new possibilities for interfering with virus growth and reactivation from latency. Our results will contribute to improved understanding of processes that are important for normal and cancerous cells. The work is laboratory-based and involves biochemistry, molecular biology, microscopy and infection of cultured cells.

Technical Summary

There are several herpesviruses that infect a high proportion of the human population. Although these viruses do not generally cause dangerous diseases, in certain groups of people, particularly the newborn and those with damaged immune systems, herpesvirus infections can become serious or even fatal. Herpesviruses are common because after an initial episode of infection, they attain a latent state so that they are carried by the infected individual for life. As there are no treatments to eradicate latent virus, an understanding of the molecular mechanisms by which herpesviruses attain, maintain and reactivate from latency is necessary for improved treatments for herpesvirus diseases. The balance between latent and lytic herpesvirus infections is governed by both viral and cellular factors, and by antiviral mechanisms that include not only the various arms of the immune defence but also mechanisms that operate via constitutively expressed proteins at the cellular level. This latter phenomenon, which is a relatively recent concept, is known as intrinsic immunity, intrinsic antiviral defence, or intrinsic resistance.

The principle aim of this programme is to decipher the mechanisms of action of herpes simplex virus type 1 (HSV-1) regulatory protein ICP0, which is required for efficient initiation of lytic infection and reactivation of latent virus. The main role of ICP0 is in counteracting intrinsic antiviral defence. We have shown that ICP0 is a ubiquitin E3 ligase that targets cellular intrinsic resistance proteins for destruction by the proteasome pathway. Current research aims to define the mechanisms of substrate targeting by ICP0 and to correlate these activities with the role of ICP0 in the regulation of viral infection. Our approaches utilise cultured cell systems of virus infection.
A major target of ICP0 is the cellular protein PML, a component of nuclear sub-structures known as PML Nuclear Bodies (PML NBs). PML and other PML NB proteins are rapidly recruited to sites associated with infecting HSV-1 genomes, a process that represents an intrinsic cellular response that represses viral gene expression. An important role of ICP0 is to inactivate this response to allow efficient infection. We have determined the molecular basis of the recruitment of PML to HSV-1 genomes and we have found that this mechanism underlies the recruitment of a number of other cellular proteins. We are extending these studies to the regulatory proteins of other herpesviruses, in particular human cytomegalovirus, to determine how their functions and mechanisms of action relate to those of ICP0. The results are expected to increase understanding of processes common to several DNA viral infections. Since components of PML NBs have been implicated in many important cellular control pathways, our experiments are likely to contribute to many aspects of cell biology research.

Publications

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Boutell C (2013) Regulation of alphaherpesvirus infections by the ICP0 family of proteins. in The Journal of general virology

 
Description EC Marie Curie Fellowship Award
Amount £154,880 (GBP)
Funding ID PIEF-GA-2009- 251948 
Organisation Marie Sklodowska-Curie Actions 
Sector Academic/University
Country Global
Start 04/2010 
End 03/2012
 
Description EC SME-STREP contract FP6-037517 'TargetHerpes'
Amount £210,000 (GBP)
Funding ID LSHG-CT-2006- 037517 
Organisation Sixth Framework Programme (FP6) 
Sector Public
Country European Union (EU)
Start 01/2007 
End 12/2009
 
Description MRCT Development Gap Funding
Amount £128,000 (GBP)
Organisation MRC-Technology 
Sector Academic/University
Country United Kingdom
Start  
 
Title Viruses, plasmids, antibodies and cell lines. 
Description Viruses, plasmids, antibodies and cell lines. We receive many tens of requests for various research tools every year, comprising literally hundreds of items. 
Type Of Material Technology assay or reagent 
Year Produced 2006 
Provided To Others? Yes  
Impact Many of our research tools are used by others in their subsequent publications. Far too many to list. 
 
Description AAV ICP0 reactivation 
Organisation University of Nantes
Department INSERM U649 (Gene Therapy Laboratory)
Country France 
Sector Academic/University 
PI Contribution Most of the experimentation
Collaborator Contribution Provision of research reagents
Impact PMID 16537633
 
Description BRCA1 study 
Organisation King's College London
Department School of Medicine KCL
Country United Kingdom 
Sector Academic/University 
PI Contribution we did some specialist experimentation and provided advice
Collaborator Contribution they did much of the experimentation
Impact PMID 16403807
 
Description CD83 study 
Organisation Friedrich-Alexander University Erlangen-Nuremberg
Department Department of Dermatology
Country Germany 
Sector Academic/University 
PI Contribution advice and provision of reagents
Collaborator Contribution experimental work
Impact PMID 17428858
 
Description HepaRG PML and Sp100 study 
Organisation Leibniz Association
Department Heinrich Pette Institute, Leibniz Institute for Experimental Virology
Country Germany 
Sector Public 
PI Contribution most of the experimentation
Collaborator Contribution provision of cell lines
Impact PMID 18160441
Start Year 2006
 
Description ICP0 and DNA repair 
Organisation Salk Institute for Biological Studies
Department Laboratory of Genetics Salk
Country United States 
Sector Charity/Non Profit 
PI Contribution Provision and exchange of reagents
Collaborator Contribution Provision and exchange of reagents
Impact PMID 20075863 PMID 21698222
Start Year 2008
 
Description ICP0 phosphorylation study 
Organisation University of Kansas
Department Department of Molecular Biosciences
Country United States 
Sector Academic/University 
PI Contribution most of the experimentation
Collaborator Contribution provision of research reagents and advice
Impact PMID 18715910
 
Description PML depletion study 
Organisation Friedrich-Alexander University Erlangen-Nuremberg
Department Institute of Clinical and Molecular Virology
Country Germany 
Sector Academic/University 
PI Contribution most of the experimentation
Collaborator Contribution provision of research reagents
Impact PMID 16873256
 
Description STAT1 and IRF3 study 
Organisation University of St Andrews
Department Centre for Biomolecular Sciences
Country United Kingdom 
Sector Academic/University 
PI Contribution most of the experimentation
Collaborator Contribution provision of research reagents
Impact PMID 18579584
Start Year 2007
 
Description SUMO proteome study 
Organisation Wellcome Trust
Department Wellcome Trust Centre for Gene Regulation and Expression
Country United Kingdom 
Sector Academic/University 
PI Contribution Design of study, experimentation, data analysis
Collaborator Contribution Design of study, experimentation, data analysis
Impact Publications will ensue in due course
Start Year 2012
 
Description proteomics study 
Organisation University of Oxford
Department Department of Biochemistry
Country United Kingdom 
Sector Academic/University 
PI Contribution provision of samples, and later confirmatory analysis of results from a proteomics screen
Collaborator Contribution They did a considerable amount of practical work and analysis
Impact PMID 19670248
 
Description MRC Virology Unit Schools day 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact An event in which pupils from several local schools receive instruction, demonstration and information on the work of the MRC Virology Unit and general issues in virology.

enhanced student interest in virology
Year(s) Of Engagement Activity 2006,2007,2008