Figure 3.

Phenotypes of srw1 disruptant. (A) Δsrw1 cells are sterile, but sterility is suppressed by deletion of Cig2 or partial inactivation of Cdc2. The h⁹⁰ leu1–32 (K153-B25) and h⁹⁰ srw1::ura4⁺ ura4-D18 leu1–32 (SY3) cells were grown to midlog phase in YEL and plated on MEA plates for conjugation at 27°C for 2 days. The h⁹⁰ srw1::ura4⁺ ura4-D18 leu1–32 (SY3) cells were transformed with pAL-srw1⁺ or pAL-X (empty pAL vector) and plated for conjugation as above. The h^+s leu1–32 (K150-A13) and h^- srw1::ura4⁺ cig2/cyc17::ura4⁺ ura4-D18 leu1–32 (SY5) cells, or h^- leu1–32 (ATCC38399) and h^+s cdc2-M35 srw1::ura4⁺ ura4-D18 leu1–32 (SY6) cells, were mixed and plated for conjugation. (B) Δsrw1 cells are unable to arrest or arrest weakly in G₁. The h^- leu1–32 (ATCC38399), h^- srw1::ura4⁺ ura4-D18 leu1–32 (SY1), h⁹⁰ leu1–32 (K153-B25), and h⁹⁰ srw1::ura4⁺ ura4-D18 leu1–32 (SY3) cells were grown in YEL to midlog phase, washed, and then incubated at 25°C in malt extract liquid (MEL) for the indicated times and analyzed by flow cytometry. (C) Deletion of Cig2 is unable to restore the G₁ arrest ability to Δsrw1 cells. The h^- leu1–32 (ATCC38399), h^- srw1::ura4⁺ ura4-D18 leu1–32 (SY1), and h^- srw1::ura4⁺ cig2/cyc17::ura4⁺ ura4-D18 leu1–32 (SY5) were grown in YEL to midlog phase, incubated at 25°C for 36 h in malt extract liquid (MEL) and analyzed by flow cytometry. The h^- srw1::ura4⁺ ura4-D18 leu1–32 (SY1) and h^- leu1–32 (ATCC38399) cells were then stained with DAPI.