Deletion of DOT1 increases the MMS sensitivity of the rad24, but not the rad9, checkpoint mutant. Tenfold serial dilutions of exponentially growing cells were spotted onto YPDA and 0.005% or 0.01% MMS plates. Strains are YP436 (wild type), YP520 (rad9), YP521 (rad24), YP522 (rad9 rad24), YP523 (rad9 dot1), YP524 (rad24 dot1), YP525 (rad9 rad24 dot1), and YP506 (dot1).