The power of yeast in modeling human mutations leading to mitochondrial disease:the case of ANT1, YARS2, DNM1L and LYRM7.

The term “Mitochondrial disease” refers to a broad range of disorders, each of which involves a mitochondrial dysfunction, in which the underlying genetic defect is often unknown. Whereas the huge increase of alleged mutations identified in single patients, for example by new generation sequencing techniques, a major challenge is to determine if these are the specific cause of the pathology, i.e. it is necessary to validate them. To prove unequivocally the causality, that must be evaluated biologically through functional analyses, the yeast Saccharomyces cerevisiae is extensively used. Here we present four different yeast models created to validate and get insight into the effect of mutations in the human genes ANT1, YARS2, DNM1L and LYRM7, involved in different mitochondrial processes, taking advantage of the presence the yeast orthologous genes. ANT1 (AAC2 in yeast) encodes for an isoform of the mitochondrial ADP/ATP carrier, exchanging cytosolic ADP for mitochondrially synthesized ATP. YARS2 (MSY1 in yeast), coding the mitochondrial tyrosyl-tRNA synthetase, is necessary for a correct mitochondrial protein synthesis. DNM1L (DNM1 in yeast) is the most important mediator of mitochondrial fission, with a role also in peroxisome division. LYRM7 (MZM1 in yeast), encoding mitochondrial LYR motif-containing protein 7, is required for the assembly of the cytochrome bc1 complex. It acts as a chaperone for Rip1 and facilitates its insertion into the complex at a late stage