A novel herpes simplex virus gene (UL49A) encodes a putative membrane protein with counterparts in other herpesviruses.

Comparative analysis of DNA sequences located between the coding regions of genes UL49 and UL50 of herpes simplex virus types 1 and 2 (HSV-1 and -2) has revealed a small open reading frame (ORF) of 91 and 87 codons respectively with the characteristics of a genuine protein-coding region. The predicted protein products are clearly related and exhibit features of membrane-inserted proteins, with potential N-proximal signal peptides and C-proximal membrane anchor regions. Counterparts are present in the other sequenced alphaherpesviruses, namely varicella-zoster virus (a previously undescribed gene, 9A) and equine herpesvirus type 1 (gene 10), in the betaherpesvirus human cytomegalovirus (gene UL73) and in the gammaherpesvirus Epstein-Barr virus (gene BLRF1). Therefore, we consider that this ORF represents an additional HSV gene (UL49A) with counterparts in all sequenced alpha-, beta- and gammaherpesviruses.