Characterization of an RNase P activity from HeLa cell mitochondria. Comparison with the cytosol RNase P activity.
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 (mtRNase P) cleaves the precursor to Escherichia coli suppressor tRNATyr at the same site as E. coli RNase P, producing the mature 5'-end of tRNATyr. 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.
Doersen
C J
CJ
Guerrier-Takada
C
C
Altman
S
S
Attardi
G
G
D000255:Adenosine Triphosphate / Q000494:pharmacology; D002412:Cations; D002853:Chromatography, Liquid; D003600:Cytosol / Q000201:enzymology; D004722:Endoribonucleases / Q000037:antagonists & inhibitors / Q000302:isolation & purification*; D029968:Escherichia coli Proteins; D006367:HeLa Cells / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008928:Mitochondria / Q000201:enzymology; D012313:RNA / Q000378:metabolism; D000077278:RNA, Mitochondrial; D043262:Ribonuclease P
D002412:Cations; D029968:Escherichia coli Proteins; D000077278:RNA, Mitochondrial; D012313:RNA; D000255:Adenosine Triphosphate; D004722:Endoribonucleases; C468368:RPP14 protein, human; D043262:Ribonuclease P; C470865:ribonuclease P, E coli