Unusual rRNA-linked complex of 50S ribosomal subunits isolated from an Escherichia coli RNase III mutant

We have isolated and characterized complexes of ribosomal subunits from Escherichia coli mutant AB301-105 connected by strands of unprocessed RNA. By electron microscopy of these complexes, the location of the 5' end of 5S RNA was established and the location of the 3' end of 23S RNA was confirmed. We also note that in these complexes insertion of 5S rRNA can proceed without the 23S-5S spacer having been processed.