Murakami Y, Yasuda H, Miyazawa H, Hanaoka F, Yamada M
Proc Natl Acad Sci U S A. 1985 Mar;82(6):1761-5. doi: 10.1073/pnas.82.6.1761.
The characterization of a temperature-sensitive mutant (tsFT20 strain, dnats) of mouse FM3A cells is reported. After incubation of tsFT20 cells at the nonpermissive temperature (39 degrees C), DNA synthesis ceased with little change in either RNA or protein synthesis. Flow-microfluorometric analysis revealed that the cell cycle of tsFT20 cells grown at 39 degrees C for 16 hr was similar to that of wild-type cells that were synchronized at the G1/S boundary and at S phase by treatment with aphidicolin, a specific inhibitor of DNA polymerase alpha. The DNA polymerase alpha activity of tsFT20 cells measured in crude cell extracts or in purified preparations was inactivated more rapidly at 39 degrees C than the activity of wild-type cells. In the growth revertants of the tsFT20 cell strain, the heat lability of DNA polymerase alpha decreased. These data suggest that tsFT20 is a temperature-sensitive mutant of DNA polymerase alpha or of a factor associated with DNA polymerase alpha that is essential for its activity.
本文报道了小鼠FM3A细胞温度敏感突变体（tsFT20株，dnats）的特性。在非允许温度（39℃）下培养tsFT20细胞后，DNA合成停止，而RNA或蛋白质合成几乎没有变化。流式微荧光分析显示，在39℃下培养16小时的tsFT20细胞的细胞周期，与用DNA聚合酶α特异性抑制剂阿非迪霉素处理后在G1/S边界和S期同步化的野生型细胞的细胞周期相似。在粗细胞提取物或纯化制剂中测得的tsFT20细胞的DNA聚合酶α活性，在39℃下比野生型细胞的活性更快失活。在tsFT20细胞株的生长回复突变体中，DNA聚合酶α的热稳定性降低。这些数据表明，tsFT20是DNA聚合酶α或与其活性相关的一种因子的温度敏感突变体，该因子对其活性至关重要。
