Plays a role in viral entry into host cells. Forms a trimeric complex at the surface of the viral envelope together with gH and gL. This complex is required for entry in host fibroblasts. Mechanistically, engages host receptor(s) including PDGFRA to mediate infection. Forms the envelope trimer complex composed of gH, gL, and gO. The trimer interacts with host PDGFRA. Host membrane associated, either via its interaction with gH, or as a type II transmembrane protein. N-glycosylated. The N-terminus is blocked. Belongs to the herpesviridae U47 family.