Absence of Ags1 promotes cell lysis and release of cytoplasmic material from either the septum region or the lateral region of the pole. (A) Sorbitol partially suppresses both cell growth arrest and cell lysis promoted by ags1⁺ repression. 81X-ags1⁺ cells were grown either without or with thiamine (−T, induced; +T, repressed) and 1.2 M sorbitol (S). Cell growth (left) and lysis (right) were monitored at the indicated times. (B) Absence of Ags1 promotes cell lysis at the septum and poles. Cells were grown as in A and visualized at the indicated times. (C) Loss of Ags1 function promotes similar cell lysis to that of Ags1 absence. mok1-664 cells were grown in YES+S and shifted to 37°C for 5 h. Arrowhead: lysis in the pole side region; arrow: lysis in the septum region. (D) ags1⁺ repression promotes cell lysis and release of cytoplasm from the division site, at the start of cell separation, resulting in the death of either one (top panels) or both sister cells (bottom panels). 81X-ags1⁺ cells were grown in EMM+T for 3 h and visualized by time lapse. Arrowhead: lysed cell. Elapsed time is shown in seconds. The percentage of each cell lysis was quantified. Bars, 5 µm.