Transformation depending on intermolecular homologous recombination is stimulated by UV damage in transfected DNA.
DNA-mediated gene transfer (DMGT) was performed in DNA repair-proficient and UV-hypersensitive, repair-deficient Chinese hamster ovary (CHO) cell lines using the UV-irradiated thymidine kinase gene from herpes simplex virus (HSV-TK). Transformation frequencies in repair-deficient CHO cell lines declined relative to repair-proficient cells with increasing UV damage in transfected DNA; approximately 3-fold higher UV fluence was required to inactivate 50% of irradiated HSV-TK plasmid molecules in repair-proficient cells. In cotransfection experiments performed with pairs of HSV-TK plasmids containing linker insertion mutations in TK coding sequences, moderate UV damage in plasmid DNA enhanced the yield of TK+ transformants resulting from homologous recombination between HSV-TK sequences up to 4-fold. These results suggest that UV damage in DNA can stimulate transformation of mammalian cells dependent on intermolecular DNA homology.
Nairn
R S
RS
University of Texas System Cancer Center, Science Park, Research Division, Smithville 78957.
Humphrey
R M
RM
Adair
G M
GM
D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D004247:DNA / Q000528:radiation effects; D004249:DNA Damage; D004260:DNA Repair; D011995:Recombination, Genetic / Q000528:radiation effects*; D013937:Thymidine Kinase / Q000235:genetics; D014162:Transfection; D014170:Transformation, Genetic / Q000528:radiation effects*; D014466:Ultraviolet Rays
D004247:DNA; D013937:Thymidine Kinase