The Role of Autophagy in Genome Stability through Suppression of Abnormal Mitosis under Starvation
Figure 6
Autophagy is important for normal cell division under nutrient starvation conditions.
(A) WT (SAY122), Δatg2 (AMY255), Δswe1 (AMY260), and Δatg2 Δswe1 (AMY261) cells were arrested at G1 by α-factor and released into SCD medium. Synchronous cultures were collected after 0.75 h and re-released into SD-N medium. The fixed cells were stained with DAPI and observed by differential interference contrast microscopy (DIC) or by fluorescence microscopy (DAPI). The arrowheads indicate cells undergoing premature mitosis (type 4 in Figure 7A). Bar, 5 µm. (B) WT (SAY122), Δatg2 (AMY255), Δswe1 (AMY260), and Δatg2 Δswe1 (AMY261) cells were grown as described in (A). The frequency of premature mitosis (type 4 in Figure 7A) was calculated. (C) ATG2 (YYK536) [66] and Δatg2 (AMY330) cells were arrested at G1 by α-factor and released into SCD medium. Synchronous cultures were collected after 0.7 h and re-released into SD-N medium or SCD medium. To monitor cell cycle progression to G1 under the nutrient-rich condition, SCD medium was supplemented with 6.7 ng/mL α-factor for re-arrest at G1. Cell lysates were prepared as described in Figure 1A, and analyzed by immunoblot with anti-myc and anti-Pgk1 antibodies. Pgk1 was used as a loading control. Uncropped images of blots are shown in Figure S5.