The mitochondrial tRNA conundrum

Predicting Mitochondrial tRNA Modification

M itochondria are integral to proper cell function, and mutations in its small genome (mtDNA) are associated with many diseases, along with the progression of normal aging [9]. While mtDNA has been extensively studied, not much is known about transcriptional variations of mitochondrial genes [3]. Recently, tRNA modifications have been the focus of intense study owing to their putative role in d...

Isolation of Saccharomyces cerevisiae mitochondrial formyltetrahydrofolic acid:methionyl-tRNA transformylase and the hybridization of mitochondrial fMet-tRNA with mitochondrial DNA.

Formyltetrahydrofolic acid:methionyl-tRNA transformylase was isolated from Saccharomyces cerevisiae mitochondria and used to prepare yeast mitochondrial [(3)H]formylmethionyl-tRNA. This fMet-tRNA hybridizes with mitochondrial DNA but not with yeast nuclear or E. coli DNA. Unlabeled mitochondrial, but not extramitochondrial, tRNA competes in this reaction. tRNA was eluted from the hybrid and fou...

THE CONUNDRUM OF EUTHANASIA

A missense mutation in the nuclear gene coding for the mitochondrial aspartyl-tRNA synthetase suppresses a mitochondrial tRNA(Asp) mutation.

The nuclear suppressor allele NSM3 in strain FF1210-6C/170-E22 (E22), which suppresses a mutation of the yeast mitochondrial tRNA(Asp)gene in Saccharomyces cerevisiae, was cloned and identified. To isolate the NSM3 allele, a genomic DNA library using the vector YEp13 was constructed from strain E22. Nine YEp13 recombinant plasmids were isolated and shown to suppress the mutation in the mitochon...

Interaction of mitochondrial initiation factor 2 with mitochondrial fMet-tRNA.

The mammalian mitochondrial genome contains a single tRNA(Met) gene that gives rise to the initiator and elongator tRNA(Met). It is generally believed that mitochondrial protein synthesis begins with formylmethionyl-tRNA, which indicates that the formylation of mitochondrial Met-tRNA specifies its participation in initiation through its interaction with initiation factor 2 (IF-2). However, rece...