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 (PubMed:28403202). Mechanistically, engages host receptor(s) including PDGFRA to mediate infection (PubMed:28403202). 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.