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Title: GLYCOPROTEINS H AND L OF MAREK'S DISEASE VIRUS FORM A HETERO-OLIGOMER ESSENTIAL FOR TRANSLOCATION AND CELL SURFACE EXPRESSION

Author
item WU, PING - MICH STATE UNIVERSITY
item REED, WILLIE - MICHIGAN STATE UNIVERSITY
item Lee, Lucy

Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/24/2000
Publication Date: 12/31/2001
Citation: WU, P., REED, W.M., LEE, L.F. GLYCOPROTEINS H AND L OF MAREK'S DISEASE VIRUS FORM A HETERO-OLIGOMER ESSENTIAL FOR TRANSLOCATION AND CELL SURFACE EXPRESSION. VIROLOGY. 2001. V. 146. P. 983-992.

Interpretive Summary: Marek's disease (MD) is an economically important cancer-like disease of chickens caused by a herpesvirus (MDV). Although vaccination has dramatically reduced the incidence of the disease, the mechanism of protection of chickens against MD including the role of the causative virus in such protection is not clearly understood. Characterization of two genes sof MDV named gL and gH and the proteins they express (produce) revealed that a combination of these two genes is required for the production of viral proteins thought to be involved in protection of chickens. The information is essential in understanding the mechanism of vaccinal immunity against this important disease and should be useful for scientists involved in developing the new generation of MD vaccines, genetically engineered vaccines.

Technical Abstract: In most herpes viruses, glycoproteins H and L form a hetero-oligomeric functional unit (gH-L) and play an important role in virus entry to host and cell-to-cell spread. In GA-MDV infected cells, a 110 kDa protein was co-precipitated with gL (25kDa) and absent wien the lystate was boiled before immunoprecipitation. Based on known sequence the size of the gH should be 110 kDa. Pulse-chase studies confirm the molecular weight of gH to range between 100 to 110 kDa. The interaction of MDV gH and gL was studied in baculovirus, fowlpox virus (FPV) and vaccinia virus MVA/T7 pol enhanced transient expression systems. In baculovirus infected Sf9 cells, gH or gL gene by itself was not sufficient for surface expression, but requires co-expression of both genes in the same cells for subcellular transportation and cell surface expression. In FPV expression system, gL was consistently secreted by the cells without gH, co expression of both genes resulted in cell surface expression. In vaccinia virus MVA/T7 pol enhanced DF-1 infected cells, however, gL was expressed as small patches on the surface without gH, but gH alone gave no surface or external protein. Co-expression of gH and gL result in positive patches of both proteins on the cell surface. These results taken together suggest that (1) MDV gH provides a membrane anchor for gL on the cell surface; (2) both gH and gL function in hetero-oligomer formation and show fusogenic properties. We have constructed several gH truncated mutants and mapped the interaction domain of gH truncated mutants and mapped the interaction domain of gH to amino acids 451-659 (SacI-HindIII fragment) to be essential for gH-L hetero-oligomeric formation.