FIG 4.

Mutations in STN1 phosphorylation sites result in a cell cycle-dependent increase in single-stranded telomere G-rich overhangs. (A) In-gel hybridization under nondenaturing conditions showed that increased signal from the single-stranded telomere G-rich overhangs can be detected in a yeast strain harboring the Cdk1 phosphorylation site mutations (stn1-T223A,S250A). (B) The same gel as in panel A, probed with a telomere-specific probe under denaturing conditions. (C and D) FACS analysis showing the DNA content of wild-type and STN1 phosphorylation mutant yeast strains from α-factor synchronization release that were used for the in-gel hybridization. (E) Quantification of the relative intensity of cell cycle-dependent generation of single-stranded telomere DNA in STN1 and stn1-T223A,S250A yeast strains. The data are derived from three independent experiments.