title: Malignant transformation of BHK21 clone 13 cells in vitro by nitrosamines--a conditional state.
abstract: All the BHK(21) Clone 13 cells transformed by dimethylnitrosamine or nitrosomethylurea, and a single "spontaneously" transformed clone obtained in our laboratory, exhibit a conditional state of the transformed phenotype. Upon growth at 38.5 degrees , they have a transformed phenotype (clonal morphology and the ability to plate in soft agar); when grown at 32 degrees , their phenotype is normal. The conditional state of these cells, however, does not extend to their growth characteristics; their plating efficiency at the two temperatures in liquid medium is similar. Conversion from the normal to the transformed phenotype and the reverse is possible by temperature shifts. A working hypothesis is proposed suggesting that this phenomenon may be caused by a temperature-sensitive mutation of a cellular gene whose product is responsible for maintaining the normal phenotype. The high temperature would then affect either the synthesis or the function of the protein carrying the temperature-sensitive alteration and, as a consequence, the transformed phenotype would be expressed.
mesh_terms: D000818:Animals; D002455:Cell Division; D002471:Cell Transformation, Neoplastic; D002999:Clone Cells; D006224:Cricetinae; D003470:Culture Media; D007668:Kidney; D009602:Nitrosamines / Q000494:pharmacology*; D009607:Nitrosourea Compounds / Q000494:pharmacology*; D010641:Phenotype; D011120:Polyomavirus; D013696:Temperature; D009626:Terminology as Topic
chemical_list: D003470:Culture Media; D009602:Nitrosamines; D009607:Nitrosourea Compounds