Kaposi's sarcoma (KS), a multicentric angiogenic tumor of mixed cellularity, is the leading neoplasm of patients with acquired deficiency syndrome (AIDS). Current molecular- and seroepidemiologic data demonstrate that KS-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV8), is the infectious cause of KS. In most cases of infection, a healthy cellular immune response likely destroys the vast majority of cells that harbor actively replicating virus. In contrast, immunosuppression can tilt this equilibrium away from this predominantly latent state to one of viral reactivation, replication and widespread dissemination. This pathogenic progression depends, in part, on high levels of KSHV production. The most remarkable pre-virion structures to appear after the initiation of viral replication are the inner capsid--the icosahedrally symmetric particles that fill the nucleus and, when fully mature, harbor the linear viral genome. In stark contrast to the successful investigations into the structure and assembly of the capsids of alpha- and betaherpesviruses, (such as herpes simplex virus 1 and cytomegalovirus, respectively), attempts to explore these aspects in the gammaherpesviruses (such as Epstein-Barr virus) have made little progress. The long-term objectives of the research we describe in the proposal are to understand KSHV structure and assembly in comparison to members of the other herpesvirus subfamilies and to place these findings into the context of KS pathogenesis. Recently, we have devised methods to purify structurally intact KSHV capsids. In this application, we propose to: 1.Purify and identify the distinct capsid species formed during lytic KSHV growth using biochemical and physical separation techniques. 2.Characterize the structural components of these capsids with biochemical, electron microscopic and mass spectrometric approaches. 3.Determine the three-dimensional structure of the capsids using computer-aided analyses of electron cryomicroscopic images. 4.Investigate KSHV capsid assembly. Understanding the details of capsid structure and assembly, an early and essential step in KSHV replication, may simultaneously identify new potential targets for therapeutic intervention.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA088768-04
Application #
6633864
Study Section
Special Emphasis Panel (ZRG1-AARR-4 (01))
Program Officer
Read-Connole, Elizabeth Lee
Project Start
2000-07-01
Project End
2005-06-30
Budget Start
2003-07-01
Budget End
2004-06-30
Support Year
4
Fiscal Year
2003
Total Cost
$265,185
Indirect Cost
Name
University of Virginia
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
065391526
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
Loftus, Matthew S; Verville, Nancy; Kedes, Dean H (2017) A Conserved Leucine Zipper Motif in Gammaherpesvirus ORF52 Is Critical for Distinct Microtubule Rearrangements. J Virol 91:
Anderson, Melissa S; Loftus, Matthew S; Kedes, Dean H (2014) Maturation and vesicle-mediated egress of primate gammaherpesvirus rhesus monkey rhadinovirus require inner tegument protein ORF52. J Virol 88:9111-28
Woodson, Evonne N; Anderson, Melissa S; Loftus, Matthew S et al. (2014) Progressive accumulation of activated ERK2 within highly stable ORF45-containing nuclear complexes promotes lytic gammaherpesvirus infection. PLoS Pathog 10:e1004066
Zhou, Z Hong; Hui, Wong Hoi; Shah, Sanket et al. (2014) Four levels of hierarchical organization, including noncovalent chainmail, brace the mature tumor herpesvirus capsid against pressurization. Structure 22:1385-98
Woodson, Evonne N; Kedes, Dean H (2012) Distinct roles for extracellular signal-regulated kinase 1 (ERK1) and ERK2 in the structure and production of a primate gammaherpesvirus. J Virol 86:9721-36
Hassman, Lynn M; Ellison, Thomas J; Kedes, Dean H (2011) KSHV infects a subset of human tonsillar B cells, driving proliferation and plasmablast differentiation. J Clin Invest 121:752-68
Nichols, Lisa A; Adang, Laura A; Kedes, Dean H (2011) Rapamycin blocks production of KSHV/HHV8: insights into the anti-tumor activity of an immunosuppressant drug. PLoS One 6:e14535
Deng, Binbin; O'Connor, Christine M; Kedes, Dean H et al. (2008) Cryo-electron tomography of Kaposi's sarcoma-associated herpesvirus capsids reveals dynamic scaffolding structures essential to capsid assembly and maturation. J Struct Biol 161:419-27
Adang, Laura A; Tomescu, Costin; Law, Wai K et al. (2007) Intracellular Kaposi's sarcoma-associated herpesvirus load determines early loss of immune synapse components. J Virol 81:5079-90
Deng, Binbin; O'Connor, Christine M; Kedes, Dean H et al. (2007) Direct visualization of the putative portal in the Kaposi's sarcoma-associated herpesvirus capsid by cryoelectron tomography. J Virol 81:3640-4

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