Two novel genes of herpes simplex virus type 1 involved in cell fusion

Herpes simplex virus type 1 (HSV-1) r mutants, which were defective in fusion function, were isolated from fusion inducing strains G7471 and G51, and classified into several groups by complementation (Yamamoto and Kabuta, 1977; Yamamoto et al. 1989). Marker rescue experiments of intact DNA from r mutants with EcoRI fragments of G7471 DNA revealed that the r mutations belonging to the groups A, B, E, F, G, and H were located in EcoRI-g, -c, -d, -h, -b, and -d fragments, respectively. The mutations belonging to the groups A, B, F, and G cover the loci affecting cell fusion which have been already reported by other investigators. The two novel mutations localized in EcoRI-d fragment were further finely mapped, and it was demonstrated that the mutations belonging to groups E and H were involved in the open reading frames UL10 and UL13, respectively.