Figure 3. Effects of protein synthesis inhibitors on processing of 17S RNA and on subunit association.

Wild-type cells were grown at 37°C in LB medium with 80 µg/ml kasugamycin (Kas) or 1.2 µg/ml chloramphenicol (Chl). (A) One µg of total RNA fraction prepared from wild-type, ▵rsgA, or drug-treated cells was electrophoresed on 1.8% agarose gel. The ratio of the amount of 17S RNA to that of 16S rRNA is shown below each lane. (B) Ribosome profiles of wild-type cells, RsgA-deletion cells and wild-type cells treated with protein synthesis inhibitors are shown. Cells were lysed with alumina powder and the cell debris was removed as described in Materials and Methods. Ten A₂₆₀ units of crude cell extracts were fractionated by 5%–20% sucrose density gradient ultracentrifugation.