Accumulation of unstable promoter-associated transcripts upon loss of the nuclear exosome subunit Rrp6p in Saccharomyces cerevisiae.
Mutations in RRP6 result in the accumulation of aberrant polyadenylated transcripts from small nucleolar RNA genes. We exploited this observation to search for novel noncoding RNA genes in the yeast genome. When RNA from rrp6Delta yeast is compared with wild-type on whole-genome microarrays, numerous intergenic loci exhibit an increased mutant/wild type signal ratio. Among these loci, we found one encoding a new C/D box small nucleolar RNA, as well as a surprising number that gave rise to heterogeneous Trf4p-polyadenylated RNAs with lengths of approximately 250-500 nt. This class of RNAs is not easily detected in wild-type cells and appears associated with promoters. Fine mapping of several such transcripts shows they originate near known promoter elements but do not usually extend far enough to act as mRNAs, and may regulate the transcription of downstream mRNAs. Rather than being uninformative transcriptional "noise," we hypothesize that these transcripts reflect important features of RNA polymerase activity at the promoter. This activity is normally undetectable in wild-type cells because the transcripts are somehow distinguished from true mRNAs and are degraded in an Rrp6p-dependent fashion in the nucleus.
Center for Molecular Biology of RNA, Department of Molecular, Cell, and Developmental Biology, Sinsheimer Laboratories, University of California, Santa Cruz, 95064, USA.
Carrie Anne
CA
Davis
Manuel
M
Ares
D015079:2-Isopropylmalate Synthase / Q000235:genetics; D000225:Adenine / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D004259:DNA-Directed DNA Polymerase / Q000235:genetics; D005095:Exoribonucleases / Q000235:genetics / Q000378:metabolism*; D063326:Exosome Multienzyme Ribonuclease Complex; D016681:Genome, Fungal / Q000235:genetics; D007168:IMP Dehydrogenase / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D021122:Protein Subunits / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics*
D021122:Protein Subunits; D012331:RNA, Fungal; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; C477283:IMD2 protein, S cerevisiae; D007168:IMP Dehydrogenase; D015079:2-Isopropylmalate Synthase; C080062:LEU4 protein, S cerevisiae; D004259:DNA-Directed DNA Polymerase; C487545:PAP2 protein, S cerevisiae; D005095:Exoribonucleases; D063326:Exosome Multienzyme Ribonuclease Complex; C112610:RRP6 protein, S cerevisiae; D000225:Adenine