Fig. 3. Histone deacetylase inhibitors suppress temperature sensitivities of S. pombe APC/C mutants. (A) Wild type and APC/C subunit mutants (cut4-533, cut9-665, nuc2-663, cut23-194, cut20-100, apc10-153, apc10-666) were cultured at 26°C and then spotted on YPD plates lacking or containing TSA (12.5 µg/ml). (B) Wild type and cut4-533 mutants were grown at 26°C and then shifted to 36°C (Time=0); at the same time TSA (12.5 µg/ml) was added to the cultures. Cell numbers were counted (left panel) and cytological phenotypes of cut4-533 mutants were observed by staining with DAPI (right panel) at the indicated time points. (C) Effects of various HDAC inhibitors (TSA, CHAP31, FK228 and TPXB) on the growth of wild type and cut4-533 mutants. Cells were cultured exponentially at 26°C, and then the temperature was shifted to 36°C after the cell numbers were adjusted to OD₆₀₀=0.01. HDAC inhibitors or the same volumes of the buffers (EtOH or DMSO) were added at the indicated concentrations, and cell numbers (OD₆₀₀) were counted after 24 hour incubation at 36°C. (D) Effects of TSA on ts or null mutants of proteins involved in the APC/C-dependent ubiquitination and proteolysis (ubcP4-140, slp1-362, ste9, mts2-1, mts3-1 and mad2). The indicated strains were spotted on YPD plates lacking or containing TSA (12.5 µg/ml). Scale bar: 10 µm.