THE EFFECT ON CELL PHENOTYPE OF THE MUTAGENIC PEPTIDE OF HERPES-SIMPLEX VIRUS TYPE-1

The transforming region of the genome of herpes simplex virus type-1 ( HSV-1) encodes a peptide that raises the mutation frequency of cells. To find the effect of this peptide on cell phenotype, three types of c ells were transfected with a shuttle vector plasmid that expressed the peptide. When immortalised rat fibroblasts were transfected they rapi dly became anchorage-independent with high efficiency, but were not tu morigenic in nude mice. When monkey kidney cells were transfected, fiv e clonal cell lines were isolated, of which one became anchorage-indep endent but was not tumorigenic in nude mice. When human oral keratinoc ytes were transfected they did not become immortalised. The peptide th erefore induced some of the features of transformation in different ce ll types, but did not induce a malignant phenotype in any cell. This s uggests that interaction with co-factors would be necessary for the pe ptide to contribute to the development of oral cancer.