The Petite Mutation in Yeasts: 50 Years On

Adaptations of Trypanosoma brucei to gradual loss of kinetoplast DNA: Trypanosoma equiperdum and Trypanosoma evansi are petite mutants of T. brucei

“…The available evidence suggests they are the equivalents in T. brucei of the petite mutants of Saccharomyces cerevisiae and other yeasts. Similarly as the petite mutants, the Dk/Ak cells are respiratory-deficient, have an accelerated mutation rate in the ␥ subunit of ATP synthase, and a disrupted mt genome, which can be easily and completely lost upon EtdBr treatment (32). In the petite mutants of yeast, it has been postulated that allelespecific mutations in the ␣ and ␥ subunits result in the formation of an aberrant ATP synthase that can prevent proton leakage, which allows their survival (33).…”

Vacuolar ATPase depletion affects mitochondrial ATPase function, kinetoplast dependency, and drug sensitivity in trypanosomes

“…A mutation in the nuclear genome-encoded γ-subunit in T. evansi or T. equiperdum can compensae for this A-subunit requirement and allows for kinetoplast loss (6). Indeed, these dyskinetoplastic trypanosomes have been referred to as petite mutants of T. brucei (10), sharing similarities with petite mutants of yeast (11). Thus, dyskinetoplastic trypanosomes use an alternative, F o -independent mode of ΔΨ mito generation involving the uncoupled F 1 sector of ATP synthase and an ADP 3-/ATP 4-carrier (6,12).…”

Deletion of conserved protein phosphatases reverses defects associated with mitochondrial DNA damage inSaccharomyces cerevisiae

“…Although mitochondria are essential organelles, neither respiration nor mtDNA is required for the viability of budding yeast on fermentable medium, because sufficient ATP can be made by glycolysis (9). However, certain nuclear mutations cause an inability to proliferate after loss of a functional mitochondrial genome (conversion from the ρ + to the ρ − state).…”

“…Maintenance of the essential ΔΨ mito in cells lacking mtDNA depends on electrogenic exchange of ATP 4− generated by glycolysis for ADP 3− produced by hydrolytic activity of the ATP synthase F 1 sector in the mitochondrial matrix (9). Consequently, when F 1 activity is blocked, ρ − cells are not able to divide.…”