Figure 2: Genomic organization of BV. The BV genome is comprised of two unique regions ( and ) in which open reading frames homologous to the UL1–UL56 and US1–US12 genes of HSV are located, respectively (a). The and regions are each flanked by repeat regions ( an , resp.) with the ‘a’ repeat present at the ends of the genome and between the internal copies of and . The and regions are enlarged in (b) to indicate the position of the following features discussed in the text: predicted ORFs (green), HSV ORFs not found in BV (blue), the origin of DNA replication in (yellow), miRNAs (asterisks), islands of reiterated sequences (magenta), and the region deleted in the E90ΔRL1 mutant (red).