title: Conservation of RNase III processing pathways and specificity in hemiascomycetes.
abstract: Rnt1p, the only known Saccharomyces cerevisiae RNase III endonuclease, plays important functions in the processing of precursors of rRNAs (pre-rRNAs) and of a large number of small nuclear RNAs (snRNAs) and small nucleolar RNAs (snoRNAs). While most eukaryotic RNases III, including the Schizosaccharomyces pombe enzyme Pac1p, cleave double-stranded RNA without sequence specificity, Rnt1p cleavage relies on the presence of terminal tetraloop structures that carry the consensus sequence AGNN. To search for the conservation of these processing signals, I have systematically analyzed predicted secondary structures of the 3' external transcribed spacer (ETS) sequences of the pre-rRNAs and of flanking sequences of snRNAs and snoRNAs from sequences available in 13 other Hemiascomycetes species. In most of these species, except in Yarrowia lipolytica, double-stranded RNA regions capped by terminal AGNN tetraloops can be found in the 3' ETS sequences of rRNA, in the 5'- or 3'-end flanking sequences of sn(o)RNAs, or in the intergenic spacers of polycistronic snoRNA transcription units. This analysis shows that RNase III processing signals and RNase III cleavage specificity are conserved in most Hemiascomycetes species but probably not in the evolutionarily more distant species Y. lipolytica.
authors.affiliation: Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California Los Angeles, Los Angeles, California 90095-1569, USA. guillom@chem.ucla.edu
authors.forename: Guillaume
authors.initials: G
authors.lastname: Chanfreau
mesh_terms: D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D001798:Blood Proteins / Q000378:metabolism*; D030541:Databases, Genetic; D047091:Eosinophil Granule Proteins; D019143:Evolution, Molecular; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D011485:Protein Binding; D026721:RNA 3' End Processing / Q000235:genetics; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional; D012330:RNA, Double-Stranded / Q000378:metabolism; D020537:RNA, Small Nucleolar / Q000235:genetics; D043244:Ribonuclease III / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism*; D012440:Saccharomyces / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D013379:Substrate Specificity
chemical_list: D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D012322:RNA Precursors; D012330:RNA, Double-Stranded; D020537:RNA, Small Nucleolar; D029701:Saccharomyces cerevisiae Proteins; D012260:Ribonucleases; C468367:RNT1 protein, S cerevisiae; D043244:Ribonuclease III