Figure 1.

Phenotype of Flag⁵ and GFP-tagged MEC1 strains. (A) Conservation of hydrophobic residues at the C-terminus of phosphoinositide three-kinase-related kinase (PIKK) family members. The C-terminal residues of the five PIKK family members found in S. cerevisiae are shown with the following consensus. (B) Yeast strains BY4741 [MEC1; wild-type (WT)], CY6076 (mec1-W2368A), CY6194 (Flag⁵-MEC1), CY6175 (Flag⁵-mec1-W2368A), a mec2-1 strain (Weinert et al. 1994; included to verify the hydroxyurea plates), CY6307 (GFP-MEC1), and CY6302 (GFP-mec1-W2368A) were grown to stationary phase diluted 1/10² and 10-fold serial dilutions were spotted onto selection plates as follows: YPD at 30°, YPD at 37°, and YPD at 30° containing 0.2 M hydroxyurea (HU).