Caenorhabditis elegans, a pluricellular model organism to screen new genes involved in mitochondrial genome maintenance.
The inheritance of functional mitochondria depends on faithful replication and transmission of mitochondrial DNA (mtDNA). A large and heterogeneous group of human disorders is associated with mitochondrial genome quantitative and qualitative anomalies. Several nuclear genes have been shown to account for these severe OXPHOS disorders. However, in several cases, the disease-causing mutations still remain unknown. Caenorhabditis elegans has been largely used for studying various biological functions because this multicellular organism has short life cycle and is easy to grow in the laboratory. Mitochondrial functions are relatively well conserved between human and C.elegans, and heteroplasmy exists in this organism as in human. C. elegans therefore represents a useful tool for studying mtDNA maintenance. Suppression by RNA interference of genes involved in mtDNA replication such as polg-1, encoding the mitochondrial DNA polymerase, results in reduced mtDNA copy number but in a normal phenotype of the F1 worms. By combining RNAi of genes involved in mtDNA maintenance and EtBr exposure, we were able to reveal a strong and specific phenotype (developmental larval arrest) associated to a severe decrease of mtDNA copy number. Moreover, we tested and validated the screen efficiency for human orthologous genes encoding mitochondrial nucleoid proteins. This allowed us to identify several genes that seem to be closely related to mtDNA maintenance in C. elegans. This work reports a first step in the further development of a large-scale screening in C. elegans that should allow to identify new genes of mtDNA maintenance whose human orthologs will obviously constitute new candidate genes for patients with quantitative or qualitative mtDNA anomalies.
Addo
Matthew Glover
MG
Université Paris-Sud, CNRS, UMR 8621, Institut de Génétique et Microbiologie, Orsay, F-91405, France.
Cossard
Raynald
R
Pichard
Damien
D
Obiri-Danso
Kwasi
K
Rötig
Agnès
A
Delahodde
Agnès
A
D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology; D000074002:DNA Polymerase gamma; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000502:physiology; D018628:Gene Dosage / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D055785:Gene Knockdown Techniques; D050259:Genes, Mitochondrial; D054629:Genome, Mitochondrial / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008928:Mitochondria / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D023421:Models, Animal; D019384:Nucleic Acid Synthesis Inhibitors; D030781:Organisms, Genetically Modified; D034622:RNA Interference / Q000502:physiology; D034741:RNA, Small Interfering / Q000494:pharmacology
D029742:Caenorhabditis elegans Proteins; D004268:DNA-Binding Proteins; D019384:Nucleic Acid Synthesis Inhibitors; D034741:RNA, Small Interfering; C526718:mtss-1 protein, C elegans; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase; C553142:Polg-1 protein, C elegans