Sequence analysis of a glycoprotein D gene homolog within the unique short segment of the EHV-1 genome

DNA sequence analysis of one-third of the unique short (Us) segment of the equine herpesvirus type 1 (EHV-1) genome revealed an open reading frame (ORF) whose translated sequence exhibits significant homology to glycoprotein D of herpes simplex virus (HSV) types 1 and 2 and to pseudorabies virus (PRV) glycoprotein 50, the gD equivalent. The ORF of the EHV-1 gD homolog lies within the pSZ-4 BamHI/KpnI fragment (map units 0.865 to 0.872 and 0.869 to 0.884) and is capable of encoding a polypeptide of 385 amino acids (43,206 molecular weight). Analysis of the nucleotide sequence revealed a complete transcriptional unit including CAAT and TATA elements and signals for polyadenylation. The predicted protein exhibits features typical of a transmembrane protein: a hydrophobic N-terminal signal sequence followed by a probable cleavage site, four potential N-linked glycosylation sites, and a hydrophobic membrane-spanning domain near the carboxyl terminus followed by a charged membrane anchor sequence.