Molecular Cloning and Sequence Analysis of the Duck Plague Virus gI Gene

The glycoprotein I (gI) gene homologue of duck plague virus (DPV) was cloned by degenerate polymerase chain reaction (PCR) and sequenced. DPV gI gene open reading frame (ORF) was 1116 bp in length and its primary translation product was a polypeptide of 371 amino acids long. Comparison with other herpesvirus revealed higher similarity, had a close evolution relationship with members of the genus Mardivirus which consisted of MeHV-1, GaHV-2 and GaHV-3, but itself branched and was independent to others. It possessed several characteristics of membrane glycoproteins, including an N-terminal hydrophobic signal peptide, an external domain containing 3 putative N-linked glycosylation sites, a C-terminal transmembrane domain, and a charged cytoplasmic tail. Moreover, gI protein of DPV contained 19 potention phosphorylation sites, 13 epitopes, a YY-motif, principally located in endoplasmic reticulum (55.6%). We inffered that DPV gI protein had good immunogenicity and probably linked to virion sorting and promoting direct cell-to-cell spread in polarized cells .