Biochemical and Structural Characterization of Proteins of the Herpesvirus Inner Tegument.
Pitts, Jared.
2014
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Abstract: The closely
related alphaherpesviruses Herpes Simplex Virus 1 (HSV-1) and Pseudorabiesvirus (PRV)
are neurotropic viruses of humans and pigs respectively. The hallmark of HSV infection
is the mucocutaneous lesions it causes during lytic infection. PRV, the causative agent
of Aujeszky's disease in pigs and other livestock, often results in lethal infection.
The mechanisms by which th... read moreese viruses replicate and are released from host cells are not
well defined. PRV and HSV-1 are two model viruses used to better characterize
alphaherpesvirus replication. In cells infected with herpesviruses, two
capsid-associated or inner-tegument proteins, UL37 and UL36 control cytosolic
trafficking of capsids by as yet poorly understood mechanisms. In this work, we set out
to further define the roles of UL36 and UL37 in viral replication though the biochemical
and structural characterization of these proteins and their complexes. For the first
time, we have purified and started biochemical characterization of the PRV UL37 protein
and regions of the PRV and HSV-1 UL36 proteins in complex with either UL37 or the
auxiliary capsid protein UL25. Notably, we have determined the crystal structure of the
N-terminal half of UL37 from PRV. The structure, which is the first for any
alphaherpesvirus inner tegument protein - reveals an elongated molecule of a complex
architecture, rich in helical bundles. Through evolutionary trace analysis we were able
to identify a novel functional region important for cell-cell spread. These results
suggest a novel role for UL37 in intracellular trafficking that promotes spread of viral
infection, expanding the repertoire of UL37 functions in intracellular virus
trafficking. Unexpectedly, the UL37 N terminus shares a structural similarity with
cellular multi-subunit tethering complexes (MTCs), which control vesicular trafficking
in eukaryotic cells by tethering transport vesicles to their destination organelles. We
attempted to determine if this structural similarity also resulted in a functional
similarity by looking for host-protein interactions mediated by UL37N. Although we
currently have been unable to validate these putative interactions, results from our
structural and mutagenesis studies support the notion that UL37 traffics capsids to
cytoplasmic budding destinations and potentially further on to cell junctions for spread
to nearby cells.
Thesis (Ph.D.)--Tufts University, 2014.
Submitted to the Dept. of Molecular Microbiology.
Advisors: Ekaterina Heldwein, and Joan Mecsas.
Committee: Andrew Camilli, Linc Sonenshein, Ralph Isberg, and John Wills.
Keywords: Microbiology, and Virology.read less - ID:
- hm50v432p
- Component ID:
- tufts:20507
- To Cite:
- DCA Citation Guide EndNote
