lm ( tk- ) mouse fibroblast cells that were biochemically transformed to the dthd kinase-positive phenotype by restriction nuclease fragments of herpes simplex virus or marmoset herpesvirus dna , all of which contained the virus dthd kinase coding region , or by hela s3 dna were more resistant to mutagenesis by n-methyl-n'-nitro-n-nitrosoguanidine or 5-bromodeoxyuridine than were dthd kinase-positive lm and lm ( tk- ) cells .
C0079941
coding region
C0007634
cells