Figure 2.—

ten1-105 is synthetic lethal with cdc13-1 and est2-Δ, and progressively elongates telomere length independent of homologous recombination. (A) Telomere length increases as strains proliferate at 23°. The initial culture for each strain (1×) was inoculated from a colony arising on SD −Trp 5-FOA plates. To obtain successive generations of the ten1-ts strains, colonies from the SD −Trp 5-FOA plates were propagated by successive streak-outs on SD −Trp plates. To obtain cultures of later generations, cells were inoculated from colonies arising on these SD −Trp plates. Strains were cultured in liquid SD −Trp media at 23° for 3 days. Genomic DNA was digested with XhoI and the Southern blot was probed with ³²P[dGT/CA]. WT (wild-type, hc160), ten1-101 (hc1862), ten1-103 (hc1863), ten1-105 (hc1864), and ten1-106 (hc1865). (B) Telomere length defect is recessive in ten1Δ/pTEN1, pten1-105 strains. Southern blot showing ten1Δ strains bearing the following plasmids: lane 1, pCN250 (TEN1) + pCN284 (TEN1); lane 2, pCN250 (TEN1) + pCN358 (ten1-105); lane 3, pCN284 (TEN1) + pCN416 (vector). Strains were grown at 23° for 4 days, and the Southern blot was performed as in A. (C) Southern blot comparing telomere length in ten1-101 and ten1-101 rad52Δ strains. Cell cultures were incubated at 23° for 4 days. Genomic DNA was digested with XhoI, and the blot was probed with ³²P[dGT/CA]. Wild type (WT, hc160), ten1-101 (hc1862), rad52Δ TEN1 (hc1722), rad52Δ ten1-101 (hc1848). (D) Plates showing growth of ten1-105 double mutant strains that were streaked simultaneously on SD −Trp and SD −Trp 5-FOA plates. All strains initially contained the pTEN1-URA3 plasmid (pCN250); only cells losing this plasmid will grow on the SD −Trp 5-FOA plates. Plates were incubated at 23° for 5 days. Strains: hc2026, hc2025, hc2027, hc2028, hc2030, hc2029, hc2031, and hc2032.