Physical characterization of the genome of feline herpesvirus-1

The physical structure of the genome of feline herpesvirus-1, a major upper respiratory tract pathogen of cats, was studied. Purified FHV-1 DNA was analyzed by restriction endonuclease and gamma 5' exonuclease digestion, blot hybridization, and electron microscopy. To facilitate further studies, nine bacteriophage clones were isolated which contained 85% of the viral genome as SalI inserts, and DNA from these clones was used in blot hybridization experiments and as substrates for restriction digest analysis. Data from these studies permitted construction of a SalI and partial HindII and EcoRI restriction maps of the viral genome. FHV-1 DNA is approximately 134 kb in size and is composed of a long (L) and a short (S) segment. The long segment (U1) is 104 kb in size and is composed of unique DNA. The adjacent S segment is approximately 30 kb in size and contains a central portion of unique DNA (Us) which is approximately 8 kb in size. The Us region is bounded by inverted repeat sequences which are 11 kb in size. Therefore, the physical structure of the FHV-1 genome is similar to the genomes of other alpha-herpesviruses.