title: Escherichia coli ribosomal ribonucleic acids are not cut from an intact precursor molecule.
abstract: Ribonuclease III-deficient strains of Escherichia coli accumulate a "30 S" RNA species. Kinetic analysis of label incorporated into rRNA species shows, however, that 30 S RNA is not the major precursor to the 16 S and 23 S RNA species is in 7- to 10-fold excess over that into 30 S RNA. The 30 S RNA species turns over with a half-life of about 2.5 min, which could account for no more than one-tenth of the incorporation into 16 S plus 23 S RNA. Thus, under these conditions RNase III-strains of E. coli do not cut rRNAs from an intact tandem precursor molecule but rather from the elongating nascent transcript, possibly by an alternate pathway not involving RNase III.
mesh_terms: D004926:Escherichia coli / Q000378:metabolism*; D005796:Genes; D008970:Molecular Weight; D009154:Mutation; D012329:RNA, Bacterial / Q000378:metabolism; D012335:RNA, Ribosomal / Q000096:biosynthesis*; D012293:Rifampin / Q000494:pharmacology; D013997:Time Factors
chemical_list: D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D012293:Rifampin