Figure 2. ISP-1-resistance activity of Sli1p in yeast cells.
(A) An ISP-1-induced growth defect is blocked by overexpression of SLI1 and YPK1. KMY1006a cells containing YEp351 (•, ○, vector alone), YEp351-Sli1 (▴, ▵) or YEp351-Ypk1 (▪, □) were grown in medium containing methanol (•, ▴, ▪) or 1 μg/ml ISP-1 (○, ▵, □) for the indicated times. Proliferation was determined by measuring A600. (B) Resistance to ISP-1 of SLI1- and YPK1-overexpressing yeast cells on SD plates. Serially diluted KMY1006a cells containing YEp351 (Vector), YEp351-Sli1 or YEp351-Ypk1 were grown on SD plates containing methanol or 0.5 or 1.0 μg/ml ISP-1 for 2 days. Serial dilutions of each strain are indicated above the panels. (C) IC50 values of ISP-1 for the wild-type (•) and sli1-null (○) strains were measured as described in the Experimental section. A595 was measured after a 48 h incubation at 30 °C. Results are expressed as a percentage of the cell density achieved by the culture in the absence of ISP-1. Data are the means±S.D. from one experiment performed in triplicate.