Analysis of bovine herpesvirus 4 genomic regions located outside the conserved gammaherpesvirus gene blocks

Bovine herpesvirus 4 (BHV-4) DNA sequences located outside the gene blocks conserved among the gamma-herpesviruses BHV-4, herpesvirus saimiri (HVS) and Epstein—Barr virus (EBV) were analysed. Twelve potential open reading frames (ORFs) were found. Protein database comparisons showed that no ORF translation products were similar to proteins encoded by alpha- or betaherpesviruses. Nevertheless, six of the ORFs were homologous in amino acid sequences to proteins encoded by HVS but apparently not to those encoded by EBV. Furthermore, the location and orientation of these six ORFs in the BHV-4 genome were similar to the corresponding ORFs in the HVS genome. No genes homologous to known cellular genes were found in the BHV-4 genome; this feature is the major difference between the BHV-4 and HVS genomes with regards to the overall gene content.