Mak11 depletion in yeast cells leads to a block in 27SB-to-7S conversion. A. Simplified drawing of different steps in rRNA maturation with the position of the oligonucleotides used for Northern blotting or primer extensions. (B to D) The amounts of large pre-rRNA and rRNA were estimated by Northern blotting (1% agarose gel with glyoxal denaturation) (B), by primer extension (C), or by Northern blotting after separation on denaturant urea-polyacrylamide (5%) gels (D). Equal amounts of total RNA were extracted at the indicated time points after addition of doxycycline from cells where endogenous MAK11 was deleted and where plasmidic TAP-MAK11 was under the control of a tetracycline-repressible promoter (strain LMA326). Oligonucleotides used to reveal the different RNAs are indicated in parentheses.