(a) Growth of S. pombe transformed with the empty vector pREP1 and pREP1-TE in the presence (+thiamine, the expression of TE is repressed in the presence of thiamine) or absence of thiamine (−thiamine, the expression of TE is induced in the absence of thiamine). (b) The observation of S. pombe cells under light microscopy and 4′,6-diamidino-2-phenylindole (DAPI)-stained cells under UV light showing the S. pombe cells transformed with pREP1-TE in the absence of thiamine became much larger and longer concomitant with bigger nuclei compared with pREP1. LM, light microscopy; UV, observation of DAPI-stained cells under UV light. (c,d) Flow cytometry analysis showing that some (about 25%) flag leaf cells of te mutant (d) have 4C DNA content compared with WT (c). (e,f) Microscopy images of transverse sections (stained with DAPI) showing that the flag leaves of te (f) have more cells with two nuclei (indicated by arrowheads) compared with WT flag leaves (e). The inset magnified parts in f showing two nuclei in one cell. (b) Scale bar, 10 μm and (e,f) 50 μm.