Human mitochondrial tRNA processing.

W Rossmanith; A Tullo; T Potuschak; R Karwan; E Sbisà

doi:10.1074/jbc.270.21.12885

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PubMed · 7759547

Human mitochondrial tRNA processing.

W Rossmanith·A Tullo·T Potuschak·R Karwan·E Sbisà

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Abstract

tRNA processing is a central event in mammalian mitochondrial gene expression. We have identified key enzymatic activities (ribonuclease P, precursor tRNA 3'-endonuclease, and ATP(CTP)-tRNA-specific nucleotidyltransferase) that are involved in HeLa cell mitochondrial tRNA maturation. Different mitochondrial tRNA precursors are cleaved precisely at the tRNA 5'- and 3'-ends in a homologous mitochondrial in vitro processing system. The cleavage at the 5'-end precedes that at the 3'-end, and the tRNAs are substrates for the specific CCA addition in the same in vitro system. Using a comparative enzymatic approach as well as biochemical and immunological techniques, we furthermore demonstrate that human cells contain two distinct enzymes that remove 5'-extensions from tRNA precursors, the previously characterized nuclear and the newly identified mitochondrial ribonuclease P. These two cellular isoenzymes have different substrate specificities that seem to be well adapted to their structurally disparate mitochondrial and nuclear tRNA substrates. This kind of approach may also help to understand the structural diversities and commonalities of tRNAs.

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Cell Compartmentation Cell Nucleus Endoribonucleases HeLa Cells Humans Mitochondria RNA Nucleotidyltransferases RNA Processing, Post-Transcriptional RNA, Catalytic RNA, Transfer RNA, Transfer, Leu RNA, Transfer, Tyr Ribonuclease P Substrate Specificity Comparative Study Journal Article Research Support, Non-U.S. Gov't

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W Rossmanith, A Tullo, T Potuschak, R Karwan, E Sbisà. 1995-05-26. Human mitochondrial tRNA processing.. https://doi.org/10.1074/jbc.270.21.12885

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