C-FOS PROTOONCOGENE TRANSIENT TRANSCRIPTION IS NEGATIVELY AFFECTED INTHE EL-ALPHA-4-2 TRANSFORMED RAT-CELL LINE

To study the effects of the regulatory phosphoprotein ICP4 of the Herp es simplex virus, (HSV), a DNA tumor virus, on the induction of gene e xpression by the epidermal growth factor (EGF), we have constructed a cell line, EL alpha 4-2, which constitutively expresses the alpha-4 ge ne product. The EL alpha 4-2 cells are derived from the rat fibroblast EL2, in which EGF induces a marked c-fos and c-myc proto-oncogene tra nscription. Here we report that in EL alpha 4-2 cells, the gene expres sion induced by EGF was negatively affected in respect to that obtaine d stimulating the parental EL2 cells. In particular, we studied the c- fos and c-myc proto-oncogene transcription induced by EGF. We found th at in EL alpha 4-2 cells the c-fos induction was dramatically reduced in comparison with the c-fos induction obtained in the parental EL2 ce lls. On the contrary, the c-myc induction by EGF was not affected by t he presence of ICP4. Finally, we compared the HSV infectivity in EL al pha 4-2 versus the EL2 cells. We showed that the virus growth capabili ty was reduced, in the cells expressing ICP4.