Figure 1.

LYS20 suppresses the CPT^s of esa1 mutants. This suppression is specific for esa1, and is dependent on the histone variant H2A.Z. (A) LYS20 suppresses the CPT^s of multiple alleles of esa1. Wild-type cells, esa1-414 mutants, and esa1-K256Q, Y325N mutants were transformed with empty vector or the LYS20 2μm plasmid. LYS20 is transcribed by its endogenous promoter, but is expressed at elevated levels due to increased copy number of the plasmid. The camptothecin plate contains 20 μg/mL camptothecin in DMSO. (B) Overexpression of LYS20 does not suppress the CPT^s of a gcn5Δ mutant. Wild-type (WT) cells were transformed with either empty vector or overexpression plasmid containing LYS20. The gcn5Δ cells were transformed with either empty vector, LYS20 overexpression plasmid, or GCN5 overexpression plasmid. Plates were synthetic complete (SC) medium lacking uracil and were incubated at 30°C. The camptothecin plate contains 20 μg/mL camptothecin in DMSO. Assays were performed as in A. (C) LYS20 suppression of the CPT^s of esa1 mutants is dependent on HTZ1. The esa1 htz1Δ double mutant was transformed with either empty vector or LYS20 overexpression plasmid. All plates are synthetic complete medium lacking uracil. The camptothecin plate contains 30 μg/mL of camptothecin in DMSO.