Figure 7.

The ntf2–2ts cell cycle arrest is MAD2 dependent. (A) MAD2Δ suppresses the ntf2–2ts cell cycle arrest. NTF2, MAD2Δ, ntf2–1ts, ntf2–1ts MAD2Δ, ntf2–2ts, and ntf2–2ts MAD2Δ cells were grown overnight at 25°C and were shifted to 37°C for 3 h. Cells were stained with an antitubulin antibody followed by antimouse Texas Red to visualize microtubules, anti-Npl3p was followed by staining with antirabbit FITC to analyze nuclear protein localization and with DAPI to visualize DNA. (B) ntf2–1ts cells exhibit a more severe protein import defect than ntf2–2ts cells. A standard import assay (Shulga et al., 1996) was used to analyze nuclear import rates. Results are plotted as the percent cells showing nuclear signal versus time for NTF2 (□), ntf2–1ts (▵), and ntf2–2ts (○).