Schematic representation of the genomic structures of the oncolytic recombinant viruses OncSyn and OncdSyn. (a) Representation of the prototypic arrangement of the HSV-1 genome with the unique long (UL) and unique short (US) regions flanked by the terminal repeat (TR) and internal repeat (IR) regions. (b) Approximate locations of the gB and gK genes. (c) An expansion of the inverted repeat region showing the approximate locations of UL54, UL55, UL56, α 0, γ134.5, α 4, α 22 and US2 genes. (d) Schematic of the DNA fragment cloned into plasmid pJM-R, which was used for insertion of the HcRed gene cassette into the viral genome in place of the NV1020 genomic deletion as described in Materials and Methods.