Figure 5. Overexpression of TOP2 confers hypersensitivity to LS1. (A) Effect of LS1 on BY4741 transformed with high copy number Yeast Tiling collection plasmids encoding TOP1, TOP2 or TOP3 (pTOP1, pTOP2, and pTOP3). Threefold-dilutions of log phase cells were patched onto YPD medium containing vehicle DMSO (control) or 10µM LS1. Overexpression of TOP2 was confirmed by quantitative western blot using secondary antibodies conjugated to infrared excitable fluorescent dyes and developed using the LI-COR fluorescent imaging system (not shown). (B) Quantitative effect of LS1 concentrations on growth of TOP2 overexpressing strain compared to cells containing the empty vector. Maximum growth rates were calculated from triplicate growth curves generated using a BioScreen C system and BGFit webserver as described in Materials & Methods.