Figure 1. eIF5A depletion impairs yeast cell growth and protein synthesis, and causes retention of polysomes.
(a) Isogenic WT (J714) and tif51a-td mutant strains (J702) were serially diluted, spotted on permissive (SCRaf + Cu2+) or non-permissive (SCGal) medium, and incubated 5 days at 25 °C. Total protein synthesis (b) and polysome profiles (c) were analyzed in tif51a-td (J702), tif32-td (YAJ22), and their isogenic WT strains following growth under non-permissive conditions. Incorporation (dpm) of [35S]Met is expressed per A600 unit, and results are representative of triplicate experiments. WT* and tif32-td* strains are isogenic. (c) Cells were treated (+) or untreated (-) with 50 μg/ml cycloheximide (CHX) prior to harvesting, and WCEs were separated on sucrose gradients and fractionated to visualize the indicated ribosomal species. P/M ratios were calculated by comparing areas under the 80S and polysome peaks; ↓polysomes indicates reduced amount of polysomes.