Mitochondrial deafness alleles confer misreading of the genetic code

Abstract

Despite the fact that important genetic diseases are caused by mutant mitochondrial ribosomes, the molecular mechanisms by which such ribosomes result in a clinical phenotype remain largely unknown. The absence of experimental models for mitochondrial diseases has also prevented the rational search for therapeutic interventions. Here, we report on the construction of bacterial hybrid ribosomes that contain various versions of the mitochondrial decoding region of ribosomal RNA. We show that the pathogenic mutations A1555G and C1494T decrease the accuracy of translation and render the ribosomal decoding site hypersusceptible to aminoglycoside antibiotics. This finding suggests misreading of the genetic code as an important molecular mechanism in disease pathogenesis.decoding ͉ mitochondria ͉ mutant rRNA ͉ ribosomes ͉ disease

Validation of a Strategy for Cancer Therapy: Delivering Aminoglycoside Drugs to Mitochondria in HeLa Cells

“…In previous study, it has been reported that AGs have a high affinity for ribosomal RNA and permeability transition in mitochondria, resulting in apoptosis via the inhibition of mitochondrial transcription or exaggerated oxidative stress, which are consistent with the molecular mechanisms for the ototoxicity and nephrotoxicity induced by AGs [24][25][26] . AGs have been clinically available as antibiotics for many years, and, unfortunately, can exert some irreversible adverse-effects, especially in the patients with a mitochondrial disease.…”

Genetic analysis of interactions with eukaryotic rRNA identify the mitoribosome as target in aminoglycoside ototoxicity

“…At the structural level, helix 44 interacts with helix 27. By modeling, nucleotide alterations in the lower stem of H44 have been suggested to affect this interaction and the relative movement between these two helices as part of the conformational change required in decoding (30). Apparently, the nature of the lower stem plays an important role in both spontaneous and drug-aggravated miscoding and determines the translational accuracy of the mutant decoding sites.…”

“…Ribosomes were purified from bacterial cell pellets as described previously (30). In brief, ribosome particles were isolated by successive centrifugations and fractionated by sucrose gradient (10 -40%) centrifugation.…”

“…Cell-free translation reactions were done as described previously (30). A reaction mixture containing M. smegmatis tRNA bulk , amino acids, S100 extract, energy mix, pyruvate kinase, and polyamines was preincubated with 30 M [ 14 Cell-Free Luciferase Translation Assays.…”

Evidence That Antibiotics Bind to Human Mitochondrial Ribosomal RNA Has Implications for Aminoglycoside Toxicity

“…For human mitochondrial H44 (hmt44) and E. coli H44 constructs, a hyperstable RNA tetraloop was inserted between the two strands (36 -39). The hmt44 construct corresponds to nucleosides 1483-1500 and 1549 -1569 of human mitochondrial 12S rRNA connected by a UUCG tetraloop (40). The E. coli H44 construct corresponds to nucleosides 1400 -1412 and 1488 -1502 of E. coli 16S rRNA (36) connected by the tetraloop GCAA.…”