Beyond replication: Division and segregation of mitochondrial DNA in kinetoplastids

- The exact mechanism of kDNA division remains mysterious.
- kDNA division must be mediated by an unidentified topoisomerase II activity.
- The tripartite attachment complex may organize kDNA replication and division.
- Diverse cellular processes can impact kDNA division and segregation.
- Methods of kDNA inheritance may have relevance in other eukaryotes.

The mitochondrial genome of kinetoplastids, called kinetoplast DNA (kDNA) is a complex structure that must be faithfully duplicated exactly once per cell cycle. Despite many years of thorough investigation into the kDNA replication mechanism, many of the molecular details of the later stages of the process, particularly kDNA division and segregation, remain mysterious. In addition, perturbation of several cellular activities, some only indirectly related to kDNA, can lead to asymmetric kDNA division and other segregation defects. This review will examine unifying features and possible explanations for these phenotypes in the context of current models for kDNA division and segregation.

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