FOLLOWING THE FATE OF HCMV GENE PRODUCTS IN HOST CELLS

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cytomegalovirus is widely spread throughout all geographic locations and socioeconomic group and infects 85% of adults in United States by 40 years of age. Our aim is to study the interactions of human cytomegalovirus with cellular proteins, and gain insights into cellular pathways modulated by herpesviruses. This study was initiated one and a half years ago in collaboration with the laboratory of Tom Shenk at Princeton University. Since then, we have isolated a variety of Protein A- or GFP-tagged HCMV viral proteins identifying their host and viral interacting partners at various stages of infections. During this last year, we have studied the interacting partners of several viral proteins, including UL83, UL121, UL38, UL99, and US22. Each of these studies highlighted new ways that HCMV utilizes to manipulate and take over the cell. Our previous studies of the viral UL38 protein demonstrated its association with HDAC1 through the interaction of a novel viral transcript UL29^28. We have now pursued this by directly studying HDAC1 in uninfected and infected cells. Isolations of HDAC1 showed that the viral infection modulates the chromatin remodeling complexes that HDAC1 associates with. Another interaction partner of UL38 was TSC2. Our studies showed that UL38 supports viral replication by blocking normal cellular responses to stress. HCMV uses the UL38-TSC1/2 interaction to inhibit TSC1/2 and ensure an active mTOR pathway, cell growth, and ribosome biogenesis. To further characterize TSC2, we performed isolation of GFP-tagged TSC2 under a normal and stressed (Serum starved) cellular environment, and are currently analyzing the differences.