FIGURE 3.

Rrp14p depletion causes a defect in 25S rRNA maturation. (A) The processing pathway of 35S pre-rRNA to the mature rRNAs in S. cerevisiae. Northern probes (a), (b), (c), (d), and (e) used in Figure 4 are shown. (B) Pulse–chase analysis of rRNA synthesis in Rrp14p-depleted cells. W303–1A transformed with pRS414 (WT, lanes 1–4) and KM1411 (GAL1–RRP14 lanes 5–8) were cultured at 30°C in SCGal–Met and Trp, shifted to SC–Met and Trp, and cultured for 18 h. Each culture was pulsed with [methyl-³H] methionine for 3 min and chased with nonradioactive methionine for the indicated times. Total RNA prepared from each sample was analyzed by electrophoresis and blotted to a membrane. The lower part of the membrane was probed for U3 snoRNA as a loading marker.