Polyadenylation and degradation of incomplete RNA polymerase i transcripts in mammalian cells

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Most transcripts in growing cells are ribosomal RNA precursors (pre-rRNA). Here, we show that in mammals, aberrant pre-rRNA transcripts generated by RNA polymerase I (Pol I) are polyadenylated and accumulate markedly after treatment with low concentrations of actinomycin D (ActD), which blocks the synthesis of full-length rRNA. The poly(A) polymerase-associated domain-containing protein 5 is required for polyadenylation, whereas the exosome is partly responsible for the degradation of the short aberrant transcripts. Thus, polyadenylation functions in the quality control of Pol I transcription in metazoan cells. The impact of excessive aberrant RNAs on the degradation machinery is an unrecognized mechanism that might contribute to biological properties of ActD.

Original languageEnglish (US)
Pages (from-to)106-111
Number of pages6
JournalEMBO Reports
Issue number2
StatePublished - Feb 1 2010


All Science Journal Classification (ASJC) codes

  • Genetics
  • Molecular Biology
  • Biochemistry

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