FAST INDUCIBLE REPAIR OF MICROINJECTED UV-IRRADIATED SV40 DNA IN MONKEY KIDNEY-CELLS

In monkey kidney cells (TC-7), microinjected with UV-irradiated (103-3 62 J/m(2)) SV40 DNA, the expression of viral antigens decreases in a U V-dose-dependent manner and the viral genes are not repaired constitut ively, When the viral DNA is microinjected 4 h after W-irradiation (40 J/m(2)) of host cells, the expression of viral antigens is restored i n all cells. The time course of restoration of viral gene expression f unction shows that in UV-irradiated cells the repair is induced rapidl y and fully within 2 h and the induced state is maintained for 24 h. I ntact viral DNA molecules, microinjected during the period of inductio n of cellular UV repair, are expressed less efficiently than UV-irradi ated viral genomes.