The effect of temperature and cell cycle length on SCE frequency in Rat-1 cells

The effects of temperature on sister-chromatid exchange (SCE) frequency in Rat-1 embryo fibroblasts was investigated by culturing cells at 35 degrees C and 39 degrees C. Cells routinely cultured at 35 degrees C had a significantly lower SCE rate (0.1903 SCE/chromosome) than those routinely cultured at 39 degrees C (2.657 SCE/chromosome). When cells routinely cultured at 35 degrees C were transferred to 39 degrees C, their SCE rate increased to that of the 39 degrees C cells. However, 39 degrees C cells transferred to 35 degrees C did not show a decrease after 24 h acclimatization but after 48 h acclimatization their SCE rate had dropped to that of the 35 degrees C cells. Cells cultured at 35 degrees C had a longer cell cycle time than cells cultured at 39 degrees C, indicating that in Rat-1 cells increased cell cycle time does not result in increased SCE.