The nuclear genes of Saccharomyces cerevisiae YHM2, ODC1 and ODC2 encode three transporters that are localized in the inner mitochondrial membrane. In this study, the roles of YHM2, ODC1 and ODC2 in the assimilation of nitrogen and in the biosynthesis of lysine have been investigated. Both the odc1Î´. odc2Î´ double knockout and the yhm2Î´ mutant grew similarly as the YPH499 wild-type strain on synthetic minimal medium (SM) containing 2% glucose and ammonia as the main nitrogen source. In contrast, the yhm2Î´. odc1Î´. odc2Î´ triple knockout exhibited a marked growth defect under the same conditions. This defect was fully restored by the individual expression of YHM2, ODC1 or ODC2 in the triple deletion strain. Furthermore, the lack of growth of yhm2Î´. odc1Î´. odc2Î´ on 2% glucose SM was rescued by the addition of glutamate, but not glutamine, to the medium. Using lysine-prototroph YPH499-derived strains, the yhm2Î´. odc1Î´. odc2Î´ knockout (but not the odc1Î´. odc2Î´ and yhm2Î´ mutants) also displayed a growth defect in lysine biosynthesis on 2% glucose SM, which was rescued by the addition of lysine and, to a lesser extent, by the addition of 2-aminoadipate. Additional analysis of the triple mutant showed that it is not respiratory-deficient and does not display mitochondrial DNA instability. These results provide evidence that only the simultaneous absence of YHM2, ODC1 and ODC2 impairs the export from the mitochondrial matrix of i) 2-oxoglutarate which is necessary for the synthesis of glutamate and ammonium fixation in the cytosol and ii) 2-oxoadipate which is required for lysine biosynthesis in the cytosol. Finally, the data presented allow one to suggest that the yhm2Î´. odc1Î´. odc2Î´ triple knockout is suitable in complementation studies aimed at assessing the pathogenic potential of human SLC25A21 (ODC) mutations.
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|Titolo:||Three mitochondrial transporters of Saccharomyces cerevisiae are essential for ammonium fixation and lysine biosynthesis in synthetic minimal medium|
|Data di pubblicazione:||2017|
|Citazione:||Three mitochondrial transporters of Saccharomyces cerevisiae are essential for ammonium fixation and lysine biosynthesis in synthetic minimal medium / Scarcia, Pasquale; Palmieri, Luigi; Agrimi, Gennaro; Palmieri, Ferdinando; Rottensteiner, H.. - In: MOLECULAR GENETICS AND METABOLISM. - ISSN 1096-7192. - (2017).|
|Appare nelle tipologie:||1.1 Articolo in rivista|