FIG. 7.

Pre-rRNA processing in GAL::nop56 and nop56-2 strains. (A) GAL::nop56 strain in permissive RSG medium (0 h) and at time points (9 to 20 h) after transfer to glucose medium. (B) nop56-2 strain grown at 23°C (0 h) and following transfer to 37°C for 9 h. Isogenic control strains were used in parallel. Total RNA was extracted and resolved in a 1.2% agarose gel containing formaldehyde. The steady-state levels of precursors and mature rRNAs were determined by hybridization with oligonucleotides a (row VIII), b (row VII), c (rows I, IV, and VI), d (row III), e (row II), and f (row V). The oligonucleotides are depicted in Fig. 1 and are described in Materials and Methods. Oligonucleotides d and e do not formally distinguish between 27SA₂ and 27SA₃, but 27SA₃ is substantially less abundant than 27SA₂, and the reduced amount of 27SA observed in rows II and III is a consequence of the reduced 27SA₂ levels.