Determination of the nucleotide sequence flanking the deletion (0.762 to 0.789 map units) in the genome of an intraperitoneally avirulent HSV-1 strain HFEM.

Herpes simplex virus type 1 (HSV-1) strain HFEM which harbours a deletion of 4.1 kbp in its genome (0.762 to 0.789 map units, HpaI DNA fragment P of HSV-1), is apathogenic for mice and tree shrews by the intraperitoneal application route. The exact position of this deletion was determined by DNA sequence analysis. This analysis was performed using the recombinant plasmid pU18HSHF-XmI-B which harbours the flanking genome regions (0.752 to 0.762 and 0.789 to 0.7895 map units) of the deletion in the genome of HSV-1 HFEM, and the recombinant plasmids pU18HSF-XmI-B, pU18HSF-AS, and pHSF-BB-BsH-D, harbouring particular regions of the genome of the virulent HSV-1 strain F at the coordinates 0.752 to 0.761, 0.786 to 0.790, and 0.762 to 0.771, respectively. The comparison of the DNA sequence of this region with the DNA sequences of the corresponding genome regions of the pathogenic HSV-1 strain F and HSV-1 strain 17 showed that the 5' end of the deletion in the genome of HSV-1 HFEM starts at the nucleotide position 3774 of the BamHI DNA fragment B from HSV-1/17. This position is 71 bp upstream of the UL/RL junction of the HSV-1 genome. The 3' terminus of the deletion ends at the nucleotide position 7226 of the BamHI DNA fragment B from HSV-1/17. The position is within the incomplete ninth repetitive box (ACTCC-CACGCACCCCC) and is located 36 bp upstream of the 3' end of the IE 110 mRNA.