Nucleotide sequence of the major DNA-binding protein gene of herpes simplex virus type 2 and a comparison with the type 1.

The nucleotide sequence of a region encompassing about 5,200 base pairs (bp) of the left side of the origin of replication in the long unique region of the herpes simplex virus type 2 (HSV-2) has been determined. This region contained the major DNA-binding protein or the infected-cell protein 8 (ICP 8) gene and 5'-part of the counterpart of HSV-1 ICP 18.5 gene. A comparison of the nucleotide sequence of the ICP8 gene between HSV-1 and HSV-2 showed an 89.8% homology. A primer extension analysis for the HSV-2 ICP 8 mRNA showed that the major transcriptional start site was mapped at 315 bp upstream of the initiation codon. A comparison of the predicted functional amino acid sequence of the ICP 8 between HSV-1 and HSV-2 revealed a striking homology (97.2%), the value of which was the highest among those of the other polypeptides encoded by HSV-1 and HSV-2. Some domains, which were shown to be required for the nuclear function, the binding to single-stranded DNA and the nuclear localization were well conserved. In addition, the nucleotide and the functional amino acid sequences of a part of the HSV-2 counterpart of the HSV-1 ICP 18.5 gene were also compared, demonstrating an 88.4% and 95.9% homology, respectively.