FIG. 2.

Telomeric repeat instability in rad27Δ strains. (A) Genomic DNA isolated from RAD27 (WT) or rad27Δ cells that were incubated at 23 or 37°C for the indicated times was digested with the restriction endonuclease XhoI and analyzed by Southern blotting. The probe used was randomly labeled telomeric repeat DNA. Y′ TRFs migrate at about 1.3 kb, and some of the other bands correspond to non-Y′ TRFs. M, end-labeled 1-kb ladder DNA serving as a size standard. (B) The same blot as in panel A, rehybridized to a probe specific for CEN4 sequences. (C) The same experiment as in panel A, except that the strains were grown at 30°C. Note that rad27Δ cells do grow at this temperature. Every day, an aliquot of the cultures was diluted into fresh medium and the cells were regrown to stationary phase (days of culturing are indicated on top of the gel). From cell density measurements, it was calculated that the cultures had grown for approximately 100 generations on day 8 (data not shown).