HeLa cell mitochondrial proteins have been shown to be the products of two separate protein-synthesizing systems; one, the general cellular mechanism, sensitive to inhibition by cycloheximide, the other, a specific mitochondrial system subject to inhibition by low concentrations of chloramphenicol (Galper, J. B., and J. E. Darnell. 1971. J. Mol. Biol 57:363). Preliminary data have suggested tha...

Cytoplasmic rRNA from the yeast mutant, mod5-1 is deficient in the modified base isopentenyladenosine and consequently migrates differently from isopentenylated wild type tRNAs on certain chromatographic systems. To determine if the mod5-1 mutation affects mitochondrial tRNA structure, the migration of mitochondrial tRNA from mod5-1 and wild type cells has been compared by reverse-phase chromat...

Mammalian mitochondrial (mt) tRNAs, which are required for mitochondrial protein synthesis, are all encoded in the mitochondrial genome, while mt aminoacyl-tRNA synthetases (aaRSs) are encoded in the nuclear genome. However, no mitochondrial homolog of glutaminyl-tRNA synthetase (GlnRS) has been identified in mammalian genomes, implying that Gln-tRNA(Gln) is synthesized via an indirect pathway ...

BACKGROUND Mitochondria are autonomous cellular organelles that oversee a variety of functions such as metabolism, energy production, calcium buffering, and cell fate determination. Most recently, mitochondrial dysfunction caused by mitochondrial mutations played important roles in the pathogenesis of asthma. However, the frequency of mitochondrial tRNA mutations in asthma is largely unknown. ...

In many organisms, mitochondria import nuclear DNA-encoded small RNAs. In yeast Saccharomyces cerevisiae, one out of two cytoplasmic isoacceptor tRNAs(Lys) is partially addressed into the organelle. Mitochondrial targeting of this tRNA was shown to depend on interaction with the precursor of mitochondrial lysyl-tRNA synthetase, preMsk1p. However, preMsk1p alone was unable to direct tRNA targeti...

Communication between the mitochondrial and nuclear genomes is vital for cellular function. The assembly of mitochondrial enzyme complexes, which produce the majority of cellular energy, requires the coordinated expression and translation of both mitochondrially and nuclear-encoded proteins. The joint genetic architecture of this system complicates the basis of mitochondrial diseases, and mutat...

Communication between the mitochondrial and nuclear genomes is vital for cellular function. The assembly of mitochondrial enzyme complexes, which produce the majority of cellular energy, requires the coordinated expression and translation of both mitochondrially and nuclear-encoded proteins. The joint genetic architecture of this system complicates the basis of mitochondrial diseases, and mutat...

All mitochondrial tRNAs in kinetoplastid protists are encoded in the nucleus and imported into the organelle. The tRNA(Trp)(CCA) can decode the standard UGG tryptophan codon but can not decode the mitochondrial UGA tryptophan codon. We show that the mitochondrial tRNA(Trp) undergoes a specific C to U nucleotide modification in the first position of the anticodon, which allows decoding of mitoch...

Fragments of mitochondrial DNA from Saccharomyces cerevisiae were joined to the Escherichia coli plasmid pBR322 by the poly(dA):poly(dT) tailing method. A total of 347 transformants containing DNA inserts were isolated. The size of the inserted DNA ranges from 0.5 to 5 kilobases. To screen for mitochondrial tRNA genes, we isolated mitochondrial tRNAs, end-labeled them with 32P, and hybridized t...

Protein synthesis (translation) stops at stop codons, codons not complemented by tRNA anticodons. tRNAs matching stops, antitermination (Ter) tRNAs, prevent translational termination, producing dysfunctional proteins. Genomes avoid tRNAs with anticodons whose complement (the anticodon of the 'antisense' tRNA) matches stops. This suggests that antisense tRNAs, which also form cloverleaves, are o...