Further characterization of a murine temperature-sensitive mutant, tsFT20 strain, containing heat-labile DNA polymerase alpha-activity

Exp Cell Res. 1986 Mar;163(1):135-42. doi: 10.1016/0014-4827(86)90565-3.


tsFT20 cells, which have temperature-sensitive DNA polymerase alpha-activity, were characterized mainly at the cellular level. The cells lost their ability to synthesize DNA immediately after a shift to non-permissive temperature. The extent of decrease in the activity of DNA polymerase alpha in whole-cell extracts was the same as that of the decrease in the DNA replication ability determined by [3H]thymidine incorporation. At 39 degrees C, tsFT20 cells lost most of their colony-forming ability in one doubling time (16 h). The cells could not grow at higher than 38 degrees C, but could grow at 37 degrees C. When tsFT20 cells were synchronized at the G1/S boundary and incubated at 39 degrees C, they could not complete the S phase, ceasing cell cycle progression in mid-S phase. A temperature shift (33 degrees C----39 degrees C) experiment indicated that the whole S phase was temperature-sensitive, whereas the G2 and M phases were not. These results confirmed that DNA polymerase alpha plays a key role in DNA replication in mammalian cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Division
  • Cell Line
  • Cell Survival
  • Clone Cells
  • Cytological Techniques
  • DNA Polymerase II / genetics
  • DNA Polymerase II / metabolism*
  • DNA Replication*
  • DNA, Neoplasm / biosynthesis
  • Interphase
  • Mammary Neoplasms, Experimental
  • Mice
  • Mitosis
  • Mutation
  • Temperature


  • DNA, Neoplasm
  • DNA Polymerase II