Prospects & Overviews
Of circles, forks and humanity: Topological organisation and replication of mammalian mitochondrial DNA
Article first published online: 2 FEB 2011
Copyright © 2011 WILEY Periodicals, Inc.
Volume 33, Issue 4, pages 290–299, April 2011
How to Cite
Pohjoismäki, J. L. O. and Goffart, S. (2011), Of circles, forks and humanity: Topological organisation and replication of mammalian mitochondrial DNA. Bioessays, 33: 290–299. doi: 10.1002/bies.201000137
- Issue published online: 14 MAR 2011
- Article first published online: 2 FEB 2011
The organisation of mammalian mitochondrial DNA (mtDNA) is more complex than usually assumed. Despite often being depicted as a simple circle, the topology of mtDNA can vary from supercoiled monomeric circles over catenanes and oligomers to complex multimeric networks. Replication of mtDNA is also not clear cut. Two different mechanisms of replication have been found in cultured cells and in most tissues: a strand-asynchronous mode involving temporary RNA coverage of one strand, and a strand-coupled mode rather resembling conventional nuclear DNA replication. In addition, a recombination-initiated replication mechanism is likely to be associated with the multimeric mtDNA networks found in human heart. Although an insight into the general principles and key factors of mtDNA organisation and maintenance has been gained over the last few years, there are many open questions regarding replication initiation, termination and physiological factors determining mtDNA organisation and replication mode. However, common themes in mtDNA maintenance across eukaryotic kingdoms can provide valuable lessons for future work.