Morphology and organization of mitochondrial nucleoids in life cycle of the yeast Saccharomyces cerevisiae

This is the authors' abstract. We don't add key points for this paper.

Mitochondrial DNA (mtDNA) is associated with specific proteins to form mitochondrial nucleoids (mt-nucleoids). We investigated morphological changes in mt-nucleoids during life cycle of the yeast, Saccharomyces cerevisiae by DAPI-fluorescence microscopy. The mt-nucleoids showed a string-of-beads appearance in log-phase cells and a small spherical one in stationary-phase cells, respectively. During meiosis and sporulation, the mt-nucleoids formed a distinct network during meiotic prophase and were distributed into spores. During the course of anaerobic culture, the mt-nucleoids formed large aggregates in stationary-phase cells. These large mt-nucleoids elongated and were dynamically dispersed into small ones during the transition from anaerobic to aerobic culture. The morphology of mt-nucleoids in rho- respiratory-deficient cells significantly varied depending on the unit length of their mtDNA sequence. We analyzed the protein components of the isolated mt-nucleoids. A DNA-binding protein Abf2p is a major component of the mt-nucleoids and plays roles in packaging mtDNA. A number of proteins other than Abf2p are also associated with mt-nucleoids. By comparison of Abf2p homologues in several yeast species, we revealed that Abf2p is a highly diverged protein among the mt-nucleoid proteins.