Topology of the Human-KSHV Host-Pathogen Genome - Project Summary/Abstract
Kaposi's sarcoma-associated herpesvirus, also referred to as human herpesvirus-8, is the etiological agent of
some of the most prevalent cancers in AIDS survivors. KSHV causes epidemic Kaposi's sarcoma, the most
common AIDS defining illness. Additionally, KSHV causes primary effusion lymphoma and multicentric
Castleman's disease. Integral to this widespread occurrence is the ability of KSHV to remain quiescent in host cells
as a latent episome until the opportunity to proliferate within a compromised immune system. While much work
has been done to understand the molecular basis of viral latency, studies of the three-dimensional organization of an
infected nucleus have been lacking. How is the KSHV episome positioned in space to keep transcription quiescent
during latency and active during lytic replication? Work on the closely related Epstein-Barr virus (EBV) discovered
that EBV hides within human heterochromatin during latency. Upon reactivation, this network of interactions
reorganizes toward human euchromatin. Contacts with the viral genome localize to OriP but do not require the
viral protein EBNA1. Whether or not a similar strategy is employed by KSHV is the focus of this proposal. Specific
Aim 1 will use chromatin conformation capture methods to determine the network of interactions between KSHV
and the human genome during latency and reactivation. The role of LANA, the EBNA1 homolog in KSHV, in
maintaining this network will also be examined. Specific Aim 2 will functionally test if tethering KSHV to specific
chromatin compartments regulates transcription. Specific Aim 3 will ask if this organization, so far only observed in
cell culture, also occurs in primary patient tissue. The sum of experiments will advance our knowledge of KSHV
host-pathogen interactions in three-dimensional space.