title: Technical knockout, a Drosophila model of mitochondrial deafness.
abstract: Mutations in mtDNA-encoded components of the mitochondrial translational apparatus are associated with diverse pathological states in humans, notably sensorineural deafness. To develop animal models of such disorders, we have manipulated the nuclear gene for mitochondrial ribosomal protein S12 in Drosophila (technical knockout, tko). The prototypic mutant tko(25t) exhibits developmental delay, bang sensitivity, impaired male courtship, and defective response to sound. On the basis of a transgenic reversion test, these phenotypes are attributable to a single substitution (L85H) at a conserved residue of the tko protein. The mutant is hypersensitive to doxycyclin, an antibiotic that selectively inhibits mitochondrial protein synthesis, and mutant larvae have greatly diminished activities of mitochondrial redox enzymes and decreased levels of mitochondrial small-subunit rRNA. A second mutation in the tko gene, Q116K, which is predicted to impair the accuracy of mitochondrial translation, results in the completely different phenotype of recessive female sterility, based on three independent transgenic insertions. We infer that the tko(25t) mutant provides a model of mitochondrial hearing impairment resulting from a quantitative deficiency of mitochondrial translational capacity.
authors.affiliation: Institute of Medical Technology & Tampere University Hospital, FIN-33014 University of Tampere, Finland.
authors.forename: J M
authors.initials: JM
authors.lastname: Toivonen
authors.forename: K M
authors.initials: KM
authors.lastname: O'Dell
authors.forename: N
authors.initials: N
authors.lastname: Petit
authors.forename: S C
authors.initials: SC
authors.lastname: Irvine
authors.forename: G K
authors.initials: GK
authors.lastname: Knight
authors.forename: M
authors.initials: M
authors.lastname: Lehtonen
authors.forename: M
authors.initials: M
authors.lastname: Longmuir
authors.forename: K
authors.initials: K
authors.lastname: Luoto
authors.forename: S
authors.initials: S
authors.lastname: Touraille
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Alziari
authors.forename: Z H
authors.initials: ZH
authors.lastname: Shah
authors.forename: H T
authors.initials: HT
authors.lastname: Jacobs
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015152:Blotting, Northern; D015139:Blotting, Southern; D002467:Cell Nucleus / Q000235:genetics; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D004272:DNA, Mitochondrial / Q000235:genetics*; D003638:Deafness / Q000235:genetics*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004318:Doxycycline / Q000494:pharmacology; D004330:Drosophila / Q000235:genetics* / Q000502:physiology; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000235:genetics; D008297:Male; D008928:Mitochondria / Q000378:metabolism*; D008957:Models, Genetic; D009154:Mutation; D009841:Oligonucleotides / Q000378:metabolism; D010084:Oxidation-Reduction; D010641:Phenotype; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D012335:RNA, Ribosomal / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics* / Q000502:physiology*; D017422:Sequence Analysis, DNA; D013016:Sound; D013997:Time Factors; D019076:Transgenes
chemical_list: D000900:Anti-Bacterial Agents; D004272:DNA, Mitochondrial; D009841:Oligonucleotides; D012335:RNA, Ribosomal; D012269:Ribosomal Proteins; C034212:ribosomal protein S12; D004318:Doxycycline