Figure 3.

Kinetics of phosphorylation of Ccq1 during telomere shortening. (A) Telomere length was analyzed by Southern hybridization for cells with ccq1-Flag, chk1-HA, and trt1Δ background collected at indicated time points following the establishment of the strain. For the culture conditions, see the Materials and Methods. (B) Whole-cell extracts (WCEs) and anti-Flag- or anti-HA-immunoprecipitates from the cells collected in A were analyzed by immunoblotting experiments using anti-Flag, anti-T93-P, or anti-HA antibody. Ccq1-Flag-expressing and Chk1-HA-expressing (60.3 kDa) cells with trt1⁺ were treated with bleomycin (Bleo) as a positive control of Chk1 phosphorylation. In addition to the major band corresponding to Ccq1-Flag protein or Chk1-HA (arrows), slower-migrating smeared Ccq1-Flag or Chk1-HA signals were observed (asterisks).