Fig. 5. Growth curves in 34-kDa-null amoebae expressing the 34 kDa and 34 kDa EF2 proteins. (A) 20°C, (B) 15°C, AX2 (), 34-kDa-null (), r34 kDa (), r34kDa EF2 ([UNK]). Cells were grown axenically in shaking cultures, and cell density was measured as a function of time after inoculation. The 34-kDa-null cells grow as well as wild-type (AX-2) at 20°C but more slowly than wild-type at 15°C. Expression of the 34 kDa EF2 slows the growth of 34-kDa-null cells at 20°C (A). Expression of the r34 kDa protein restores the normal growth rate to that of 34-kDa-null cells at 15°C. By contrast, 34 kDa EF2 fails to rescue the slow growth phenotype (B).