温度敏感变种细胞ts22及其回复株的初步鉴定

CHARACTERIZATION OF A TEMPERATURE-SENSITIVE MUTANT TS22 AND ITS REVERTANT

本文从Balb/3T3的温度敏感变种ts 22中分离出一株自发回复株ts 22 R,其自发回复频率小于10^(-7)。测定变种ts 22和回复株ts 22 R细胞的DNA、RNA和蛋白质合成的结果表明:变种ts22是一种DNA合成缺失的温度敏感细胞,而其回复株ts 22 R已不再具有温度敏感的特性。

A spontaneous revertant ts22R was isolated from a temperature-sensitive mutant of Balb/3T3 cells ts22. The reversion frequency for ts22 was less than 10-7. At the non-permissive temperature of 38.8℃, revertant ts22R cells grew as well as wild-type 3T3 cells and exhibited the ability to form colonies, while mutant ts22 cells lost viability after shift to 38.8℃. Further determination of macromolecular synthesis in mutant and revertant cells showed that ts22 was temperature-sensitive in DNA synthesis. RNA and protein synthesis in two types of cells were not affected by the temperature shift. DNA synthesis in revertant ts22R cells was no longer temperature-sensitive. Therefore,ts22 is a DNA' mutant and ts22R is a true revertant of the mutant.