Scott Terhune, PhD
Assistant Professor, Dept of Microbiology & Molecular Genetics BBC
P: (414) 955-2511 | F: (414) 955-6568 | E: sterhune[at]mcw.edu
- Dominique Carter (IDP)
- Tarin Bigley (MSTP)
- Justin Reitsma (IDP)
- Kristen Westdorp (IDP)
The objective of my research is to determine the functions of human cytomegalovirus (HCMV) proteins through identifying protein-protein interactions during infection using mass spectrometry. HCMV is a member of the beta-herpesvirus family. Infections in healthy children and adults are generally asymptomatic. However, primary infection or reactivation of the latent virus in immunologically immature or compromised individuals results in life threatening disease. The HCMV genome contains more than 200 open reading frames (ORF) but it is unclear which ORFs are expressed during infection. Expression of viral genes occurs through a regulated cascade whereby immediate early genes are expressed first, followed by early and late genes.
My work focuses upon the role of viral proteins expressed at immediate early and early times during HCMV infection that are necessary to maintain the cell in a permissive state for virus replication. Using powerful genetics available for manipulating infectious BAC (bacterial artificial chromosome) clones of HCMV strains, we have constructed a library of viruses with each virus containing a different epitope tagged open reading frame (Fig. 1). These tags include the TAP (tandem affinity purification), YFP (yellow fluorescence protein), and FLAG epitope. Viral and cellular interacting proteins are isolated from infected cells using a rapid one-step immuno-affinity purification and subsequently identified by mass spectrometry (Fig. 2).
This approach of combining viral genetics and proteomics has been successfully used to demonstrate the function of the viral early protein, pUL38. During infection, HCMV pUL38 interacts with multiple protein complexes, including tuberous sclerosis protein complex (TSC1/TSC2) and the HDAC1-containing nucleosome remodeling and deacetylation complex (Mi-2/NuRD). TSC1/2 functions by integrating cellular stress signals resulting, in part, in a block in protein translation. pUL38 is necessary and sufficient to interfere with TSC1/2 function during infection. The pUL38/NuRD interaction is necessary for efficient virus replication and we hypothesize that this occurs through modulating both viral and cellular gene expression.
Projects in my lab currently include:
- Further characterization of the role of the pUL38/NuRD complex during infection.
- Determining the role of additional HCMV proteins of unknown function during infection using genetics and proteomics approaches.
- We are also interested in investigating the role of class I and II histone deacetylases as well as members of the interferon-inducible p200 family using epitope tagged cellular proteins and mass spectrometry during HCMV infection.