A new quadrannulate species of Orobdella, Orobdellamasaakikuroiwai sp. n., from the mountainous region of central Honshu, Japan is described. This is only the second small species known within this genus, with a body length of less than 4 cm for mature individuals. Phylogenetic analyses using nuclear 18S rDNA and histone H3 as well as mitochondrial COI, tRNA(Cys), tRNA(Met), 12S, tRNA(Val), 16S...

Groupers of the family Epinephelidae are a diverse and economically valuable group of reef fishes. To investigate the evolution of their mitochondrial genomes we characterized and compared these genomes among 22 species, 17 newly sequenced. Among these fishes we identified three distinct genome organizations, two of them never previously reported in vertebrates. In 19 of these species, mitochon...

Presence of the dihydrouridine (D) stem in the mitochondrial cysteine tRNA is unusually variable among lepidosaurian reptiles. Phylogenetic and comparative analyses of cysteine tRNA gene sequences identify eight parallel losses of the D-stem, resulting in D-arm replacement loops. Sampling within the monophyletic Acrodonta provides no evidence for reversal. Slipped-strand mispairing of noncontig...

Human polypyrimidine tract-binding protein PTB is a multifunctional RNA-binding protein with four RNA recognition motifs (RRM1 to RRM4). PTB is a nucleocytoplasmic shuttle protein that functions as a key regulator of alternative pre-mRNA splicing in the nucleoplasm and promotes internal ribosome entry site-mediated translation initiation of viral and cellular mRNAs in the cytoplasm. Here, we de...

Mammalian mitochondrial translational initiation factor 3 (IF3(mt)) promotes initiation complex formation on mitochondrial 55S ribosomes in the presence of IF2(mt), fMet-tRNA and poly(A,U,G). The mature form of IF3(mt) is predicted to be 247 residues. Alignment of IF3(mt) with bacterial IF3 indicates that it has a central region with 20-30% identity to the bacterial factors. Both the N- and C-t...

Opisthorchis felineus, a hepatic trematode, is the causative agent of opisthorchiasis, a dangerous disease in both human beings and animals. Opisthorchiasis is widespread in Russia, especially Western Siberia. The purpose of the present study was to determine the complete mitochondrial DNA sequence of this flatworm. Two parallel methods were employed: (1) capillary electrophoresis to sequence t...

The pathogenetic mechanism of the mitochondrial tRNA A3243G transition associated with the mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome has been investigated in transmitochondrial cell lines constructed by transfer of mutant mitochondrial DNA (mtDNA)-carrying mitochondria from three genetically unrelated MELAS patients or of isogenic wild-ty...

Due to a complete lack of the tRNA genes in the mitochondrial genome of Trypanosoma brucei, all tRNAs needed for mitochondrial translation have to be imported into the organelle from the cytosol. A previous study showed that the modified nucleotide s(2)U could act as a negative determinant for mitochondrial tRNA import in another kinetoplastid, Leishmania tarentolae. We have investigated whethe...

Mitochondrial DNA (mtDNA) regions corresponding to two major tRNA gene clusters were amplified and sequenced for the Japanese pit viper, himehabu. In one of these clusters, which in most vertebrates characterized to date contains three tightly connected genes for tRNA(Ile), and tRNA(Gln), and tRNA(Met), a sequence of approximately 1.3 kb was found to be inserted between the genes for tRNA(Ile) ...

A growing number of mutated mitochondrial tRNA genes have been found associated with severe human diseases. To investigate the potential interference of such mutations with the primordial function of tRNAs, i.e. their aminoacylation by cognate aminoacyl-tRNA synthetases, a human mitochondrial in vitro aminoacylation system specific for isoleucine has been established. Both native tRNAIleand iso...