A sequence motif within trypanosome precursor tRNAs influences abundance and mitochondrial localization

Mol Cell Biol. 2003 Dec;23(24):9061-72. doi: 10.1128/MCB.23.24.9061-9072.2003.

Abstract

Trypanosoma brucei lacks mitochondrial genes encoding tRNAs and must import nuclearly encoded tRNAs from the cytosol. The mechanism and specificity of this process remain unclear. We have identified a unique sequence motif, YGG(C/A)RRC, upstream of the genes encoding mitochondrially localized tRNAs in T. brucei. Both in vitro import studies and in vivo transfection studies indicate that deletion of the YGG(C/A)RRC sequence alters mitochondrial localization of tRNA(Leu), and in vivo studies also show a decrease in the cellular abundance of tRNA(Leu). These studies provide direct evidence for cis-acting RNA motifs within precursor tRNAs that facilitate the selection of tRNAs for mitochondrial import in trypanosomes. Furthermore, we found that mutations to the YGG(C/A)RRC sequence also altered the intracellular distribution of other endogenous tRNAs, suggesting a general role for this sequence in tRNA trafficking in trypanosomes.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Biological Transport, Active
  • Conserved Sequence
  • Cytosol / metabolism
  • Mitochondria / metabolism
  • Molecular Sequence Data
  • Mutation
  • RNA Precursors / genetics*
  • RNA Precursors / metabolism*
  • RNA Processing, Post-Transcriptional
  • RNA, Protozoan / genetics*
  • RNA, Protozoan / metabolism*
  • RNA, Transfer, Leu / genetics*
  • RNA, Transfer, Leu / metabolism*
  • Sequence Deletion
  • Sequence Homology, Nucleic Acid
  • Transfection
  • Trypanosoma brucei brucei / genetics*
  • Trypanosoma brucei brucei / metabolism*

Substances

  • RNA Precursors
  • RNA, Protozoan
  • RNA, Transfer, Leu
  • pre-tRNA(Leu)