Molecular Genetics of Herpes Simplex Virus II. Mapping of the Major Viral Glycoproteins and of the Genetic Loci Specifying the Social Behavior of Infected Cells

We have mapped the location in herpes simplex virus (HSV) DNA of (i) three mutations at different loci (syn loci) which alter the social behavior of infected cells from clumping of rounded cells to polykaryocytosis, (ii) a mutation which determines the accumulation of one major glycoprotein VP8.0(C(2))], and (iii) the sequences encoding four major virus glycoproteins VP8.0(C(2)), VP7(B(2)), VP8.5(A), and VP19E(D(2))]. The experimental design and results were as follows. (i) Analysis of HSV-1 x HSV-2 recombinants showed that the sequences encoding the VP19E(D(2)) glycoprotein map in the S component, whereas the sequences encoding the other three major glycoproteins are in two locations in the L component of HSV DNA. The templates specifying the HSV-1 and HSV-2 glycoprotein VP8.0(C(2)) appear not to be colinear; we isolated recombinants specifying glycoproteins comigrating in sodium dodecyl sulfate-polyacrylamide gels with VP8.0(C(2)) of both HSV-1 and HSV-2. (ii) Marker rescue of a ts mutant defective in accumulation of glycoprotein VP7(B(2)) showed that the mutation maps within a region containing the sequences encoding that glycoprotein. (iii) Marker transfer experiments involving transfection of rabbit skin cells with donor HSV-1(F) DNA and fragments from several donor strains causing fusion of Vero or both Vero and HEp-2 cells revealed the existence of three syn loci specifying the social behavior of cells and one locus (Cr) determining the accumulation of glycoprotein VP8.0(C(2)). The Cr locus maps to the right of the template specifying VP8.0(C(2)) glycoprotein. Loci syn 1 and syn 2 map at or near the Cr locus but can be segregated from it. Locus syn 3 maps at or near the template specifying glycoproteins VP7(B(2)) and VP8.5(A). The expression of mutations in the syn 1 and syn 3 loci appear to be cell type dependent, in that recombinants with these mutations fuse Vero cells but not HEp-2 cells. Recipients of the syn 2 locus or of both syn 2 and syn 1 loci fuse both Vero and HEp-2 cells.