3´-end sequencing of poly(A)+ RNA in wild-type Saccharomyces cerevisiae and nuclear exosome mutant strains

The nuclear exosome performs critical functions in non-coding RNA processing, and in diverse surveillance functions including the quality control of mRNP formation, and in the removal of pervasive transcripts. Most non-coding RNAs and pervasive nascent transcripts are targeted by the Nrd1p-Nab3p-Sen1p (NNS) complex to terminate Pol II transcription coupled to nuclear exosome degradation or 3´-end trimming. Prior to nuclear exosome activity, the Trf4p-Air2p-Mtr4p polyadenylation complex adds an oligo-A tail to exosome substrates. Inactivating exosome activity stabilizes and lengthens these A-tails. We utilized high-throughput 3´-end poly(A)+ sequencing to identify at nucleotide resolution the 3´ ends targeted by the nuclear exosome, and determine the sites of NNS-dependent termination genome-wide. Overall design: 3´-end mapping of wild-type and various nuclear exosome mutant strains, either using gene knockouts or the anchor away system to conditionally deplete FRB-tagged proteins from the nucleus

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Roy K, Gabunilas J, Gillespie A, Ngo D, Chanfreau GF