The role of the 3' external transcribed spacer in yeast pre-rRNA processing.
We have undertaken a deletion analysis of the 3' external transcribed spacer (3' ETS) in the pre-rRNA of Saccharomyces cerevisiae. A stem loop structure immediately 3' to the 25 S rRNA region is necessary and sufficient for processing of the 3' ETS. This is believed to be by cotranscriptional cleavage by Rnt1p, the yeast homologue of RNase III. In addition, this stem-loop is required for cleavage of site A3 by RNase MRP and for processing at site B1L, in the 3' region of ITS1. Processing at an upstream site in ITS1, site A2, and at sites in the 5' external transcribed spacer are not affected, even by complete deletion of the 3' ETS. We conclude that processing in the 3' ETS and in ITS1 is coupled. This would constitute a quality control that prevents synthesis of the 5. 8 S rRNA and 5' end maturation of the 25 S rRNA in transcripts which are incomplete due to premature transcription termination.
Allmang
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Institute of Cell and Molecular Biology, University of Edinburgh, Edinburgh, EH9 3JR, United Kingdom.
Tollervey
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D001483:Base Sequence; D004722:Endoribonucleases / Q000378:metabolism; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009690:Nucleic Acid Conformation; D012322:RNA Precursors / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012331:RNA, Fungal / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000378:metabolism*; D043244:Ribonuclease III; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D014158:Transcription, Genetic
D012322:RNA Precursors; D012331:RNA, Fungal; D012335:RNA, Ribosomal; D029701:Saccharomyces cerevisiae Proteins; C065039:RNA, ribosomal, 25S; D004722:Endoribonucleases; C468367:RNT1 protein, S cerevisiae; D043244:Ribonuclease III