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. 1997 Dec;8(12):2475–2486. doi: 10.1091/mbc.8.12.2475

Figure 4.

Figure 4

Figure 4

Δsrw1 wee1–50 cells die of mitotic catastrophe. (A) Δsrw1 wee1–50 cells are unable to grow on YEA plate at 36°C. (B) Δsrw1 wee1–50 cells die of mitotic catastrophe, which is blocked by hydroxyurea. The h+s srw1::ura4+ wee1–50 ura4-D18 leu1–32 (SY4) cells were grown to midlog phase in PM+N medium at 25°C and incubated at 36°C for 6 h in PM+N medium with or without 12 mM hydroxyurea. Cells were fixed with 70% ethanol and stained with DAPI. (C) Overexpression of srw1+ rescues Δmik1 wee1–50 cells from mitotic catastrophe. The h- mik1::ura4+ wee1–50 ura4–294 leu1–32 (HM43) cells were transformed with pREP1-srw1+* (deleted for G-tail) or pREP1-X(empty vector), grown to midlog phase at 25°C in PM+N medium, and then shifted to 36°C. Cells were fixed with 70% ethanol and stained with DAPI. (D)Δsrw1 wee1–50 cells are unable to grow even at 30°C on PM-N plate. The h+s srw1::ura4+ wee1–50 ura4-D18 leu1–32 (SY4), wee1–50 leu1–32 (HM65), and h- mik1::ura4+ wee1–50 ura4–294 leu1–32 (HM43) cells were streaked on PM-N, PM+N, and YEA plates and incubated at 30°C and 25°C. (E) Δsrw1 wee1–50 cells lose viability in nitrogen-poor medium due to mitotic catastrophe. The h+s srw1::ura4+ wee1–50 ura4-D18 leu1–32 (SY4) and h- mik1::ura4+ wee1–50 ura4–294 leu1–32 (HM43) cells were grown to midlog phase in PM+N medium, incubated in PM+N or PM-N at 25°C for 6 h, and transferred to fresh PM+N or PM-N medium at 32°C followed by further incubation for the indicated time. The percent cell viability was calculated by dividing the number of colonies formed on YEA plates at 25°C by that of 0 h after appropriate dilution. The number of cells in cut phenotype was counted under the microscope after staining with DAPI.