HERPESVIRUS ICP18.5 AND DNA-BINDING PROTEIN GENES ARE CONSERVED IN EQUINE HERPESVIRUS-1

The genome of equine herpesvirus-1 (EHV-1) contained three open readin g frames (ORFs) in a 3.9 kbp BamHI-SmaI fragment at 0.38-0.41 map unit s in the long unique region. The most 5' ORF encoded the carboxy termi nus of a protein with 45-55 percent amino acid homology to the DNA-bin ding proteins (ICP8-DBP) of four other alphaherpesviruses. The middle ORF translated to a polypeptide of 775 residues with 43-55% homology t o the ICP18.5 proteins. The most 3' ORF encoded the EHV-1 glycoprotein B (gB) gene. Three mRNAs of 4.3, 4.4-4.8, and 3.5-3.9 kb (correspondi ng to the three sequenced ORFs) were all transcribed from the same str and. The gene order of this group was conserved in all herpesviruses e xamined.