Figure 2.

Mmm2p is required for mitochondrial shape and maintenance of mtDNA nucleoids. (A) Mitochondria and mtDNA in mmm2Δ, mmm1Δ, and mmm1Δ mmm2Δ cells. Wild-type strain MY4, mmm1Δ strain MY1, mmm2Δ strain MY2, and mmm1Δ mmm2Δ strain MY3 were grown in glycerol/ethanol medium, stained with Mitofluor 589 (Mitochondria) or DAPI (mtDNA), and then examined by DIC and fluorescence microscopy. Representative images of cells are shown. N, staining of the nucleus by DAPI. Bar, 3 μm. (B) Classification of mmm2Δ phenotypes. mmm2Δ strain MY2 was stained with DiOC₆ and then examined by DIC and fluorescence microscopy. Cells were sorted into four groups based on their mitochondrial appearance. Class I, distorted and sausage-shaped mitochondria; Class II, spherical-shaped mitochondria; Class III, sheet-like mitochondria; Class IV, a mixture of distorted and spherical-shaped mitochondria. A representative from each group is shown, and the percentage of cells (out of 107 total cells examined) in each category is indicated to the right of each image. Bar, 3 μm.