Characterization of an RNase P activity from HeLa cell mitochondria. Comparison with the cytosol RNase P activity

C. J. Doersen, C. Guerrier-Takada, S. Altman, G. Attardi

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148 Scopus citations


A ribonuclease P-like activity was partially purified from HeLa cell mitochondria by DEAE-cellulose and octyl-Sepharose chromatography. RNase P-like activity can be quantitatively recovered from intact mitochondrial preparations treated with micrococcal nuclease, strongly suggesting that the enzyme is localized within the organelles. Mitochondrial RNase P (mt-RNase P) cleaves the precursor to Escherichia coli suppressor tRNA(Tyr) at the same site as E. coli RNase P, producing the mature 5'-end of tRNA(Tyr). The sensitivity of mtRNase P to pretreatment with nucleases or Pronase indicates that the enzyme has essential RNA and protein components. Although the ionic requirements of mtRNase P are similar to those of the RNase P activity isolated from the post-mitochondrial cytosol fraction, the chromatographic properties of mtRNase P are distinct. Mitochondrial RNase P is probably a part of the mitochondrial RNA processing machinery of mammalian mitochondria, being responsible for the endonucleolytic cleavage of the RNA transcripts at the 5'-side of the tRNA sequences.

Original languageEnglish (US)
Pages (from-to)5942-5949
Number of pages8
JournalJournal of Biological Chemistry
Issue number10
StatePublished - 1985
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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