S. cerevisiae cells that express rrp40-W195R or rrp40-W195A as the sole copy of Rrp40 show impaired growth at 37°. Growth of rrp40∆ cells containing only wild-type RRP40 or mutant rrp40 (G8A, S87A, W195R, W195A, or W195F) plasmid was analyzed by: (A) Serial dilution, spotting on minimal medium plates, and growth at indicated temperatures for 1 day (Day 1) or 2 days (Day 2). (B) Growth in liquid culture at 37° and optical density measurements over time. (C) Serial dilution, spotting on minimal medium plates containing 5-FU, and growth at indicated temperatures.