FIGURE 2.

The region of Jjj1 required for interaction with Rei1 is necessary for efficient ribosome biogenesis. A, 10-fold serial dilutions of Δjjj1 cells carrying WT JJJ1, the indicated JJJ1 mutant gene, or no JJJ1 gene (−) on a plasmid were spotted on a minimal medium plate and incubated at 23 °C for 2 days. B, Δjjj1 cells expressing Arx1-GFP and Jjj1 (WT), no Jjj1 (−), or the indicated variants were grown to an A₆₀₀ of 0.3–0.6 at 23 °C prior to imaging. Upper, representative images showing the Arx1-GFP localization. Lower, the percentages of cells with Class I, II, or III Arx1-GFP localization are shown. A minimum of 100 cells was counted for each. Part. Cyto, partial cytosolic localization; Disp, dispersed localization. C, Δjjj1 cells expressing WT Jjj1-HA, Jjj1_Δ363–534-HA, or no Jjj1 (Δjjj1) were grown at 23 °C and lysed in Buffer I. Ten A₂₅₄ units of lysate were centrifuged through a 5–50% sucrose gradient. Upper, the A₂₅₄ was monitored and plotted versus the time course of fraction collection. The positions of 40 S, 60 S, 80 S, polysomes, and half-mer migration are labeled. Lower, fractions were analyzed for the presence of Jjj1_Δ363–534-HA and WT Jjj1-HA by immunoblot analysis using HA-specific antibody.