Fission Yeast Strain Selection Protocol

All the S. pombe strains used in this study are shown in Table 1. Selection for strains containing telomere cassettes was performed in Edinburgh minimal medium with sodium glutamate substituted for ammonium chloride (EMMG) without uracil and with appropriate amino acid supplements and 100 μg/ml HygroGold (InvivoGen) (81 (link)). Nonselective growth of strains bearing the telomere cassettes was done in EMMG with adenine, histidine, uracil, leucine, lysine, and arginine (EMMG plus AHULKR) and without hygromycin. Preparation of 10 mM ahTET stock and plates was performed as described previously (34 (link)). 5-Fluoroorotic acid (5-FOA) plates were yeast nitrogen base plates with 1 mg/ml 5-FOA (Toronto Research Chemicals, Inc.) (http://www-bcf.usc.edu/~forsburg/drugs.html) and with the appropriate supplements. All recombinant DNA procedures were carried out in NEB 5-alpha (New England BioLabs) and TOP10 (Life Technologies) competent cells.