title: DNA-mediated gene transfer in Chinese hamster ovary cells: clonal variation in transfer efficiency.
abstract: Thymidine kinase-deficient Chinese hamster ovary (CHO) cells were genetically transformed with the BamHI restriction fragment encoding the thymidine kinase gene of herpes simplex virus (HSV-tk). We have observed considerable clonal variation among independent CHO sublines with respect to transformation competence for the DNA-mediated gene transfer of HSV-tk. Transformation frequencies greater than or equal to 3 X 10(-4) were observed consistently in one subline, with a transformation efficiency of approximately 1 transformant per ng viral gene. The frequency and efficiency of transformation we observed in this system are at least 10-fold greater than those previously reported for DNA-mediated transformation of CHO cells by HSV-tk. All of the CHO HSV-tk+ transformants examined were stable for the transferred genotype in the absence of selection, and all showed evidence of co-transformation by unselected plasmid pBR322 sequences.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002472:Cell Transformation, Viral; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D004274:DNA, Recombinant / Q000378:metabolism*; D005260:Female; D005796:Genes; D051379:Mice; D009693:Nucleic Acid Hybridization; D010053:Ovary; D018139:Simplexvirus / Q000201:enzymology / Q000235:genetics*; D013937:Thymidine Kinase / Q000172:deficiency / Q000235:genetics*
chemical_list: D004274:DNA, Recombinant; D013937:Thymidine Kinase