Transcriptional analysis of two simian varicella virus glycoprotein genes which are homologous to varicella-zoster virus gpI (gE) and gpIV (gI).

Simian varicella virus (SVV) causes a natural, varicella-like disease in nonhuman primates. The unique short region of the SVV genome contains four open reading frames (ORFs), two of which encode glycoproteins that exhibit extensive homology with varicella-zoster virus (VZV) gpIV (gI) and gpI (gE). Northern hybridization, primer extension, and RNase protection analyses were employed to define precisely the transcripts mapping to the SVV gpIV and gpI genes. A total of five transcripts composing two coterminal families of RNAs were mapped to the SVV gpIV and gpI ORF region. Based on transcriptional mapping and previous DNA sequence analysis, two transcripts 1.3 and 2.2 kb in size were assigned to the SVV gpIV and gpI genes, respectively. The transcriptional patterns described in this study for the SVV gpIV and gpI ORFs are analogous to those previously reported for the homologous glycoproteins genes encoding the herpes simplex virus type 1 Us7 (gI) and Us8 (gE) and VZV gpIV and gpI genes. In addition, the transcriptional start site for the VZV gpI RNA was determined. DNA alignments of the promoter regions for the SVV and VZV gpIV and gpI genes revealed a number of cis-acting elements which are conserved between the two viruses. The characterization of SVV glycoprotein genes will facilitate future studies to define their role in SVV pathogenesis and immunity and assist in the construction of recombinant vaccines which could be evaluated in the simian varicella model.