Surveillance of noncoding RNA production by the exosome. A variety of small noncoding RNAs are transcribed from the genome. These RNAs are polyadenylated by the TRAMP complex, which facilitates their degradation by the exosome. Some of these transcripts appear to participate in regulatory events before their degradation. The molecular model of the human exosome was generated using PyMOL from PDB coordinates 2NN6 deposited by Liu et al. . CUTs, cryptic untranslated transcripts; PASRs, promoter-associated short RNAs; UNTs, upstream noncoding transcripts.