FIGURE 1:

Dosage suppression of cbk1-8 mutants. (A) High-copy BCK2 and RPH1 plasmids partially suppress the temperature sensitivity of cbk1-8 mutants. A 10-fold dilution series of cbk1-8 cells (FLY2884) expressing high-copy plasmids pGP564 (empty vector), pCBK1 (pGP564-CBK1), pBCK2 (pGP564-BCK2), pRPH1 (pGP564-RPH1), and pBCK2-RPH1 (pGP564-BCK2-RPH1) were grown at 22, 34, and 37°C. pBCK2 and pRPH1 partially suppress the conditional lethality of cbk1-8 cells at 34°C. Note that pBCK2-RPH1 is a more potent dosage suppressor of cbk1-8 than pBCK2 or pRPH1. (B) Dosage suppression of cbk1-8 drug sensitivity at 22°C. A 10-fold dilution series of cbk1-8 cells expressing the designated plasmids were grown on plates containing 100 μg/ml calcofluor white, 15 mM caffeine, and 50 μg/ml hygromycin B at 22°C. At 22°C, cbk1-8 cells are sensitive to calcofluor white, caffeine, and hygromycin B. pBCK2 and pBCK2-RPH1 plasmids suppress the calcofluor white sensitivity. pBCK2 and pRPH1 suppress the caffeine sensitivity of cbk1-8 cells to the same extent as pBCK2-RPH1. None of the plasmids suppresses the hygromycin B sensitivity of cbk1-8 cells.