Fraction collection, slot blot, and primer extension analysis (see Materials and Methods). (A) A260 units/mL of ribosome fractions collected from sucrose gradients (Mg++ concentration 6 mM/10 mM at lysis/sedimentation) for wild-type MG1655/I-::tet (closed squares) and ΔrluD::kan/I-::tet mutant (open squares). (Numbers below each graph are the fractions pooled for the ribosomal subunits indicated.) (B) Open boxes represent mature rRNA species, lines represent precursor sequences, and solid bars indicate probes used for slot blot hybridization (2 and 4) and primer extension analysis (1 and 3). (C) Equal amounts (5 μg) of RNA from pooled ribosomal fractions were transferred to nitrocellulose membranes and probed with the indicated oligonucleotides. (D) Equal amounts (0.5 μg) of RNA from the same pooled fractions were analyzed by primer extension using the indicated oligonucleotides.
