Genomic characterization of two predominant genotypes of herpes simplex virus type 1.

Genomic profiles of 66 strains of herpes simplex virus type 1 (HSV-1) isolated in Japan were investigated with regard to restriction fragment length polymorphism (RFLP) and length variation of fragments containing reiterations. There were two predominant genotypes of F1 and F35, and the genomic characteristics of each were studied. The nucleotide change between F1 and F35 was estimated to be 1.5%. An RFLP marker (VR23) peculiar to genotype F35 was identified as the first case of genomic marker specific to a predominant genotype of HSV-1, and is the diagnostic marker of F35. The a sequences (repeating in an HSV-1 genome and containing reiterations) of F35 were cleaved by SacII on the DR4 (direct repeat 4) stretch, while a sequences of F1 had a rearranged DR4 and were resistant to SacII digestion. Thus, analyses of fragments containing reiterations, such as a sequences, can serve to classify HSV-1 strains as well as for purpose of differentiation. The proportion of strains derived from primary infection to those from recurrent infection was higher in strains of F35 than in those of F1, and this genotypic difference within HSV-1 may possibly influence clinical manifestations.