tRNA modification in the mitochondrion

Modifications near the anticodon and near the 3' end of tRNAs tend to affect interaction of the tRNA with mRNA within ribosomes and with tRNA synthetases, respectively. Modifications in other regions, typically in the "core" of the tRNA tend to affect folding and stability of the tRNA (reviewed in Hou et al. 2015). The unusual modification 5-taurinomethyl-2-thiouridine-34 in the anticodon of at least 3 tRNAs is found only in mammalian mitochondria and mutations that affect the responsible biosynthetic enzymes (GTPBP3, MTO1, TRMU) cause mitochondrial dysfunction and disease (reviewed in Torres et al. 2014).