Figure 1.

Genes encoding M. tuberculosis or human mitochondrial LeuRSs rescue a respiration-deficient yeast strain that contains a null allele of the gene encoding mitochondrial LeuRS. Strain QBY320 was transformed with plasmids expressing LeuRS originating from M. tuberculosis (pC³-Mtb), human mitochondria (pC³-Hs), and yeast mitochondria (pQB184), as well as a vector only control (pQB153). Four Leu⁺ transformants from each were purified on 5-fluoroorotic acid to remove the maintenance plasmid and then were tested for complementation of the MSL1 null strain on glycerol medium as described in Materials and Methods. Two sets of colonies for the parent (W303) and null (QBY276) strain also were tested as controls. Dark colonies reflect red pigmentation because of an ade2 mutation (see Materials and Methods).