Role of activated ras oncogene in radiation response of the Rat-1 cell line

This paper determines if activated ras oncogene induces radiation resistance, with use of Rat-1 cell line as a model. Two Rat-1 cell lines (MR4 and MR7) had been transfected with the c-ras T24 gene under the control of the mouse heavy metal-inducible MT (metallothionein I) promoter. The amount of gene expression was regulated by treating the cells with zinc. Response to irradiation with Cs-137 gamma rays was assessed by performing multiple paired clonogenic cell survival assays. The nontransfected control Rat-1 line was compared with the transfected MR7 line. MR4, the second transfected line, was treated with zinc (100 μM ZnSO4) and compared with nontreated MR4 control cells