question: How are cryptic unstable transcripts (CUTs) defined?
answer: This resource includes deletions of small nuclear RNAs (snRNAs), transfer RNAs (tRNAs), small nucleolar RNAs (snoRNAs), and other annotated ncRNAs as well as the more recently identified stable unannotated transcripts (SUTs) and cryptic unstable transcripts (CUTs) whose functions are largely unknown There is extensive transcription throughout the eukaryotic genome resulting in both antisense transcripts from coding regions and cryptic unstable transcripts (CUTs) from intergenic regions These cryptic unstable transcripts (CUTs) are rapidly degraded by the nuclear exosome. These results suggest that transcription termination of CUTs directed by Nrd1 and Nab3 is a prerequisite for rapid degradation by the nuclear exosome.  It is likely that many of these are cryptic unstable transcripts (CUTs), which are rapidly degraded and whose function(s) within the cell are still unclear, while others may be novel functional transcripts. These recently identified transcripts either exist stably in cells (stable unannotated transcripts, SUTs) or are rapidly degraded by the RNA surveillance pathway (cryptic unstable transcripts, CUTs)