Fig. 6. Proliferation of tsBN2 cells expressing RCC1 isoforms. GFP-RCC1 and GFP-RCC1, and their respective S11A non-phosphorylatable mutants, were transiently expressed in tsBN2 cells. Following transfection, cells were split equally between dishes and kept at the permissive temperature (32°C) for 24 hours (day 0), then shifted to the restrictive temperature (39.7°C) for the time periods indicated. The number of GFP-positive cells (A) and DAPI-positive cells (B) is expressed as a percentage of the number of each present at day 0. Mean of four values for each data point ± s.d. is shown. About 60 GFP-positive cells and more than 150 DAPI-positive cells were counted for each data point at day 0. (C) Number of DAPI-positive cells expressed as a multiple of those initially transfected at day 0. In order to account for the few cells that survive at the restrictive temperature in the absence of transfected RCC1, the mean percentage of surviving DAPI-positive cells from an untransfected control were first subtracted from the mean percentage of total DAPI-positive cells in each transfected sample. The resultant value was then divided by the mean percentage of transfected cells determined at day 0.