title: Characterization of a separate small domain derived from the 5' end of 23S rRNA of an alpha-proteobacterium.
abstract: We demonstrate the presence of a separate processed domain derived from the 5' end of 23S rRNA in ribosomes of Rhodopseudomonas palustris, a member of the alpha-++proteobacteria. Previous sequencing studies predicted intervening sequences (IVS) at homologous positions within the 23S rRNA genes of several alpha-proteobacteria, including R.palustris, and we find a processed 23S rRNA 5' domain in unfractionated RNA from several species. 5.8S rRNA from eukaryotic cytoplasmic large subunit ribosomes and the bacterial processed 23S rRNA 5' domain share homology, possess similar structures and are both derived by processing of large precursors. However, the internal transcribed spacer regions or IVSs separating them from the main large subunit rRNAs are evolutionarily unrelated. Consistent with the difference in sequence, we find that the site and mechanism of IVS processing also differs. Rhodopseudomonas palustris IVS-containing RNA precursors are cleaved in vitro by Escherichia coli RNase III or a similar activity present in R.palustris extracts at a processing site distinct from that found in eukaryotic systems and this results in only partial processing of the IVS. Surprisingly, in a reaction unlike characterized cases of eubacterial IVS processing, an RNA segment larger than the corresponding DNA insertion is removed which contains conserved sequences. These sequences, by analogy, serve to link the 23S rRNA 5' rRNA domains or 5.8S rRNAs to the main portion of other prokaryotic 23S rRNAs or to eukaryotic 28S rRNAs, respectively.
authors.affiliation: Research Institute of Innovative Technology for the Earth, 9-2, Kizugawadai, Kizu, Soraku, Kyoto 619-0292, Japan. zahnk@rite.or.jp
authors.forename: K
authors.initials: K
authors.lastname: Zahn
authors.forename: M
authors.initials: M
authors.lastname: Inui
authors.forename: H
authors.initials: H
authors.lastname: Yukawa
mesh_terms: D020561:Alphaproteobacteria / Q000235:genetics; D001483:Base Sequence; D002499:Centrifugation, Density Gradient; D004722:Endoribonucleases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins; D019143:Evolution, Molecular; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D012313:RNA / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012338:RNA, Ribosomal, 23S / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D012241:Rhodopseudomonas / Q000166:cytology / Q000201:enzymology / Q000235:genetics*; D043244:Ribonuclease III; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid
chemical_list: D029968:Escherichia coli Proteins; D012322:RNA Precursors; D012329:RNA, Bacterial; D012338:RNA, Ribosomal, 23S; D012313:RNA; D004722:Endoribonucleases; D043244:Ribonuclease III; C468366:ribonuclease III, E coli