SRA

Mitochondria are essential organelles due to their role in oxidative phosphorylation and biosynthesis of essential molecules. Saccharomyces cerevisiae is a popular model organism for studying mitochondrial biology, as the robustness of S. cerevisiae to mitochondrial mutations makes it one of the few organisms in which mitochondrial DNA can be edited. Engineering of mitochondrial DNA requires mitochondrial selectable marker genes, such as the widely used ARG8 gene, encoding acetylornithine aminotransferase, which catalyzes an essential step in the arginine biosynthesis.In this study, ARG8 as well as ARG2 was deleted in S. cerevisiae, to investigate their potential as mitochondrial markers. It was found that upon deletion of ARG2 cells are still able to produce a limited amount of biomass and can bypass the deletion when uracil is provided. Additionally, arginine auxotrophy of an arg8 mutant was frequently reverted, resulting in arginine prototrophy and loss of respiration. The phenotype was caused by a mutation in UME6, causing de-repression of the CAR2 gene, providing the cells with an alternative route for arginine biosynthesis. Deletion of both ARG8 and CAR2 resulted in a fully arginine auxotrophic strain which can be used for mitochondrial targeting- and expression studies using the ARG8 marker.