Epstein-Barr virus Glycoproteins BDLF2 and BMRF2 are Important for Efficient Infection and Spread in Oral Epithelia
Restricted (Penn State Only)
- Author:
- Walston, Joshua
- Graduate Program:
- Biomedical Sciences (PHD)
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- December 09, 2022
- Committee Members:
- Ralph Keil, Program Head/Chair
Neil Christensen, Major Field Member
Gregory Yochum, Outside Unit & Field Member
Jianming Hu, Major Field Member
Jeffery Sample, Major Field Member
Clare Sample, Chair & Dissertation Advisor - Keywords:
- EBV
BDLF2
BMRF2
Cell-to-cell
Stratified Epithelium
Herpesvirus - Abstract:
- Infection of the ubiquitous Epstein-Barr virus (EBV) is associated with multiple epithelial cancers or lesions such as nasopharyngeal carcinoma, gastric cancer, and oral hairy leukoplakia. Despite EBV’s prevalence and many years devoted to its study, the EBV lifecycle in oral epithelium remains to be fully elucidated. Our lab has determined that organotypic, or raft, cultures of primary keratinocytes support productive replication of EBV. In rafts, infection appears in isolated cells productively replicating virus, followed by spread over time throughout the tissue. We have studied the EBV glycoprotein complex BDLF2/BMRF2, proteins previously uncharacterized during EBV infection of stratified epithelium. The related murine herpesvirus MHV-68 utilizes the glycoprotein complex gp48/ORF58, proteins homologous to EBV BDLF2/BMRF2, for efficient protein trafficking and viral spread. Previous studies of BDLF2 demonstrate that it requires BMRF2 for trafficking, just as gp48 requires ORF58 for trafficking. BMRF2 has been reported to be important for viral attachment through an RGD motif, and for viral spread within pseudostratified epithelium via a cytoplasmic YLLV sorting signal. We have utilized recombinant EBV to study the effects of loss of BDLF2/BMRF2 and of mutation of the BMRF2 RGD motif. Prior studies have highlighted the importance of cytoskeleton remodeling and cell-junctions for herpesvirus spread in multiple models of infection, and so we believed that mutation or loss of BMRF2 or BDLF2 might hinder spread of EBV within oral epithelium. We found that loss of BDLF2 severely hindered viral infection and BDLF2 appeared essential for virus spread in the stratified epithelium of raft cultures, while loss or mutation of BMRF2 does not result in such dramatic changes, suggesting it may play a supplemental role during infection. Further elucidation of the role and functions of these glycoproteins may assist future efforts to inhibit EBV infection and spread in oral epithelium, and to reduce EBV-associated pathologies.