Unveiling the mystery of mitochondrial DNA replication in yeasts.

Conventional DNA replication is initiated from specific origins and requires the synthesis of RNA primers for both the leading and lagging strands. In contrast, the replication of yeast mitochondrial DNA is origin-independent. The replication of the leading strand is likely primed by recombinational structures and proceeded by a rolling circle mechanism.

The N-terminal intrinsically disordered domain of Mgm101p is localized to the mitochondrial nucleoid.

The mitochondrial genome maintenance gene, MGM101, is essential for yeasts that depend on mitochondrial DNA replication. Previously, in Saccharomyces cerevisiae, it has been found that the carboxy-terminal two-thirds of Mgm101p has a functional core. Furthermore, there is a high level of amino acid sequence conservation in this region from widely diverse species.

Studying mitochondria in an attractive model: Schizosaccharomyces pombe.

The fission yeast Schizosaccharomyces pombe, widely used for studies of cell cycle control and differentiation, provides an alternative and complementary model to the budding yeast Saccharomyces cerevisiae for studies of nucleo-mitochondrial interactions. There are striking similarities between S. pombe and mammalian cells, in both their respiratory physiology and their mitochondrial genome structure.

A functional core of the mitochondrial genome maintenance protein Mgm101p in Saccharomyces cerevisiae determined with a temperature-conditional allele.

Analysis of Mgm101p isolated from mitochondria shows that the mature protein of 27.6 kDa lacks 22 amino acids from the N-terminus. This mitochondrial targeting sequence has been incorporated in the design of oligonucleotides used to determine a functional core of Mgm101p.