Glycoproteins H and L of Marek's disease virus form a hetero-oligomer essential for translocation and cell surface expression

Glycoproteins H and L form a hetero-oligomeric complex (gH-L) which plays a n important role in virus entry to host cells and cell-to-cell infection in herpesviruses. Interaction of gH and gL is considered to be critical for t he biological function of these two glycoproteins. To investigate the inter action of MDV gH and gL, both gH and gL were expressed in in vitro cell cul ture systems using indirect immunofluorescence assay with gH and gL antibod ies. The results suggested that co-expression of gH and gL in the same cell s are required and necessary for both gH and gL subcellular translocation a nd cell surface expression. gL expressed in recombinant fowlpox virus (rFPV ) infected chicken embryo fibroblasts (CEF) was consistently secreted into the culture medium. The primary peptide of gL binds with that of gH in the cytosol or ER lumen. By binding with gH, gL could anchor itself on the cell surface allowing for surface expression and viral spread to uninfected cel ls. The binding domain of gH was mapped to the amino acids 451-659 (SacI-Hi ndIII) fragment and was essential for gH-L complex formation.