Characterization of Ubiquitin-Activating Enzyme Uba1 in the Nucleus by Its Mammalian Temperature-Sensitive Mutant
Figure 8
Incubation at 39°C led to an increase in endogenous geminin-positive tsTM3 cells.
(A) Wild-type CHO-K1 or ts mutant tsTM3 cells were grown at 34°C or incubated at 39°C for 12 hours and fixed. Next, endogenous geminin was indirectly immunolabeled with Alexa 594, and cells were counterstained with Hoechst 33342. Scale bar, 10 µm. Higher magnification views are shown to the right of the low-power images. Incubation at 39°C led to an increase in geminin-positive tsTM3 cells. Localization of geminin to the nucleolus was found in tsTM3 cells at 39°C. (B) Quantitative analyses of the numbers of cells expressing geminin in CHO-K1 and tsTM3 cells. Cells expressing geminin, like those shown in panel (A), were counted and are expressed as a ratio with standard deviation of at least three experiments. Incubation at 39°C increased the number of tsTM3 cells expressing geminin, although differences from values at 34°C were not significant.