Specific detection of fission yeast primary septum reveals septum and cleavage furrow ingression during early anaphase independent of mitosis completion
Fig 5
The activation of septum synthesis in early anaphase B depends on SIN function, but not on the asymmetric SIN in the SPB.
(A) Sid2-Mob1 kinase complex localizes to the division site just after Bgs1 localization and coincident with the septation onset. Cells were grown and imaged as in Fig 1. (B) Septation start is delayed when the function of Sid2 is compromised. Cells were grown in YES at 25°C, shifted to 28°C for 4 h and imaged as in Fig 1. The data of cells of B are developed in Table 1 and Table 3. (C, D) Septation start coincides with the asymmetric disappearance of Cdc7 from one SPB. Cells were grown in YES at 25°C (wild-type, C) or released at 25°C after 3.5 h of cell cycle arrest at 36°C (cdc25-22, D), and imaged by time-lapse fluorescence microscopy (maximum-intensity projections of 7 z slices at 0.4 μm intervals for Cdc7-GFP and 1 medial z slice for CW-staining, 1 min elapsed time). (E) Timely activation of septum synthesis does not depend on SIN asymmetry. Defective SIN-Inhibitory Phosphatase (SIP) complex csc2Δ cells were examined as in C. The data of cells of C, D and E are developed in S2 Table. Graphs to the right show the total fluorescence of Cdc7-GFP in each SPB in the series to the left. Dashed lines in graphs correspond to the arrowheads in the series. A.U., arbitrary units. Symbols are as in Fig 1. Bars, 5 μm.