To determine if Mre11 and CDK2 interact directly, we used the yeast two-hybrid system40. When cloned into either configura¬tion of bait and prey plasmid, Mre11 and CDK2 showed a readily detectable interaction (Fig. 4a and Supplementary Fig. 4). Notably, Mre11ATLD1 reduced the interaction with CDK2 to near background levels (Fig. 4a). By contrast, Mre11ATLD1 showed no reduction in the ability to homodimerize, indicating that the C-terminal deletion does not globally affect the Mre11 protein (Fig. 4a).