FIGURE 4.

Inhibition of polyamine biosynthesis by the spermidine synthase inhibitor CHA increased cell sensitivity to Hst 5. A, WT cells were cultured overnight in medium with or without 5 mm CHA, and then tested for Hst 5 sensitivity. WT cells cultured with CHA showed significantly (p < 0.01) increased Hst 5 mediated killing as compared with cells grown in medium only, which was accompanied by (B) an increase in the expression level of DUR3 but not DUR31 in 5 mm CHA-treated cells; thus indicating the role of Dur3p for Hst 5 toxicity.