Helicase activity plays a crucial role for RNase R function in vivo and for RNA metabolism

Sk Tofajjen Hossain, Murray P Deutscher

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

RNase R is a 3' to 5' hydrolytic exoribonuclease that has the unusual ability to digest highly structured RNA. The enzyme possesses an intrinsic, ATP-dependent RNA helicase activity that is essential in vitro for efficient nuclease activity against double-stranded RNA substrates, particularly at lower temperatures, with more stable RNA duplexes, and for duplexes with short 3' overhangs. Here, we inquired whether the helicase activity was also important for RNase R function in vivo and forRNAmetabolism.Wefind that strains containing a helicasedeficient RNase R due to mutations in its ATP-binding Walker motifs exhibit growth defects at low temperatures. Most importantly, cells also lacking polynucleotide phosphorylase (PNPase), and dependent for growth on RNase R, grow extremely poorly at 34, 37, and 42 °C and do not grow at all at 31 °C. Northern analysis revealed that in these cells, fragments of 16S and 23S rRNA accumulate to high levels, leading to interference with ribosome maturation and ultimately to cell death. These findings indicate that the intrinsic helicase activity of RNase R is required for its proper functioning in vivo and for effective RNA metabolism.

Original languageEnglish (US)
Pages (from-to)9438-9443
Number of pages6
JournalJournal of Biological Chemistry
Volume291
Issue number18
DOIs
StatePublished - 2016

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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