The impact of respiratory complex dysfunction in Caenorhabditis elegans

Mitochondria are essential organelles of eukaryotic cells, responsible for the generation of the majority of the energy carrier molecule ATP. This essential process of energy production is achieved by oxidative phosphorylation (OXPHOS), facilitated by a set of proteins collectively named the electron transport chain (ETC). Loss of mitochondrial function has devastating effects on the cell and is usually associated with a disease state. The model organism Caenorhabditis elegans (C. elegans) is genetically tractable, has large progeny broods and provides information on a whole animal level. In recent years, it has become an established model organism for identifying connections between mitochondrial dysfunction and lifespan. Using bioinformatics combined with protein modelling, the C. elegans B0491.5 protein has been identified as the homologue of NDUFA11, a key mammalian component of the electron transport chain complex I accessory subunit. NDUFA11 is linked to complex assembly and stabilisation; loss of NDUFA11 results in a reduction of complex I and metabolic perturbation. The research presented in my thesis investigates the impact of reducing B0491.5 activity on whole animal physiology and mitochondrial biochemistry. I have shown through a genetic knockout that b0419.5 is an essential gene, and using RNAi to suppress b0491.5 expression, that in its absence animal growth is delayed and reproductive capabilities severely reduced. Depleting B0491.5 also has a significant impact on mitochondrial physiology, disrupting respiration activity and seemingly limiting animals to achieve only minimum energy demands. Mitochondrial biochemistry establishes B0491.5 enrichment in mitochondria, in addition to validating the protein’s association with complex I. Furthermore, evidence is presented suggesting B0491.5 participates in the formation of complex I containing supercomplexes. When B0491.5 is reduced, there is disruption to supercomplex formation and decreased levels