Date of Award
Doctor of Philosophy (PhD)
David C. Johnson
The focus of my research has been to identify cellular proteins which facilitate herpes simplex virus (HSV) entry and cell-to-cell spread. Previous research had demonstrated that HSV glycoprotein gD bound to a cell surface protein which was required by the virus for entry into cells. I began efforts to identify and characterize cellular proteins which bound to a soluble form of gD which lacked the transmembrane domain and cytoplasmic tail. I demonstrated that both the 275 kDa and 46 kDa mannose 6-phosphate receptors (MPRs) bound to soluble and full-length gD. The interaction between gD and the 275 kDa MPR was mediated primarily through mannose 6-phosphate (M6P) residues present on N-linked oligosaccharides. There was evidence that interactions between HSV and MPRs were important for virus entry. When the interaction between HSV and MPRs was blocked, HSV entry into cells was inhibited by 60% to 80%. However, HSV was able to enter into a mouse cell line that did not express MPRs. In addition to functioning during entry, there was evidence that MPRs also played a role in HSV egress or cell-to-cell spread. Blocking MPRs or preventing the addition of M6P residues to HSV glycoproteins resulted in inefficient viral egress and cell-to-cell spread. Therefore blocking the ability of HSV to interact with MPRs renders the virus less efficient at entry, cell-to-cell spread, and egress. To determine whether MPRs functioned during HSV egress from cells, I examined the intracellular localization of HSV gD by indirect immunofluorescence. I demonstrated that the HSV proteins gD, gI, and HSV capsids localized to the same compartment as the 275 kDa MPR. However, the intracellular retention of gD was not dependent on M6P residues. These data provide evidence that HSV proteins accumulate in intracellular compartments. These intracellular compartments represent a site involved in HSV exit from cells.
Brunetti, Craig R., "The role of mannose 6-phosphate receptors during herpes simplex virus replication and glycoprotein D binding" (1997). Open Access Dissertations and Theses. Paper 3336.