N-terminal domain of borna disease virus G (p56) protein is sufficient forvirus receptor recognition and cell entry

Borna disease virus (BDV) surface glycoprotein (GP) (p56) has a predicted m olecular mass of 56 kDa. Due to extensive posttranslational glycosylation t he protein migrates as a polypeptide of 84 kDa (gp84), The processing of gp 84 by the cellular protease furin generates gp43, which corresponds to the C-terminal part of gp84, Both gp84 and gp43 have been implicated in viral e ntry involving receptor-mediated endocytosis and pa-dependent fusion, We ha ve investigated the domains of BDV p56 involved in virus entry. For this, w e used a pseudotype approach based on a recently developed recombinant vesi cular stomatitis virus (VSV) in which the gene for green fluorescent protei n was substituted for the VSV G protein gene (VSV DeltaG*). Complementation of VSV DeltaG* with BDV p56 resulted in infectious VSV DeltaG* pseudotypes that contained both BDV gp84 and gp43. BDV-VSV chimeric GPs that contained the N-terminal 244 amino acids of BDV p56 and amino acids 421 to 511 of VS V G protein were efficiently incorporated into VSV DeltaG* particles, and t he resulting pseudotype virions were neutralized by BDV-specific antiserum. These findings indicate that the N-terminal part of BDV p56 is sufficient for receptor recognition and virus entry.