In quiescence, S. pombe assemble a unique MT bundle associated with the SPB. (A) Cells expressing GFP-Atb2 (green) and Sfi1-CFP (red) are shown (top). The variation of the number of MT bundles per cell is presented as a function of time (bottom; glucose exhaustion is marked by a red dashed line; n > 200 cells per time point). (B) The number of MTs per bundle increases upon quiescence entry (p-values are indicated; n > 100 cells per time point). (C) The Q-MT bundle is associated with the SPB (N = 2 experiments and n > 100 cells). Examples of quiescent cells (5 d) expressing GFP-Atb2 (green), Sfi1-CFP (red), and Cut11-RFP (blue). Bars, 2 µm. (D and E) The Q-MT bundle visualized longitudinally (D) and transversally (E) by freeze substitution EM in WT cells (7 d). Green arrows point at MTs, red arrowheads point at the nuclear membrane, and a blue arrow indicates the SPB. (F) Distance distribution between two MTs measured using images in E. (G) Using serial section electron tomograms, 3D models of Q-MT bundles were designed. MTs are in green, the nuclear membrane is in red, and the SPB is in blue. Two cells are shown using different view angles.