Chapter 24 Induction and Isolation of Cold-Sensitive Lines of Chinese Hamster Cells

Abstract

Publisher Summary It is possible, using modifications of standard procedures for the selection of heat-sensitive variants, to obtain cold-sensitive mammalian cell lines. The frequency of ribosomal subunit assembly defective mutants among these lines is apparently not as high as in prokaryotes. These cold-sensitive mammalian lines should however, provide an additional source of cells with conditional defects in essential cellular functions. Cold-sensitive mutants of prokaryotes have been a valuable source of cells with defects in essential cellular processes. Some of these cold-sensitive mutations are in genes for which no heat-sensitive counterparts have been discovered. Cold-sensitive strains of bacteria include an especially high frequency of ribosomal subunit assembly defective mutants. This phenomenon is probably explained by the observation that ribosome assembly is a highly temperature-dependent process. Subunit assembly defective mutants also appear among cold-sensitive strains of fungi, but with a much lower frequency than in bacteria. The mutagenesis and selection temperatures were reversed, and the times for each treatment were altered to compensate for the difference in the growth rates of wild-type cells at high and low temperatures.