Modifying the Mitochondrial Genome Alexander N. Patananan, Ting-Hsiang Wu, Pei-Yu Chiou, Michael A. Teitell  Cell Metabolism  Volume 23, Issue 5, Pages 785-796 (May 2016) DOI: 10.1016/j.cmet.2016.04.004 Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 1 Transferring Mitochondria for Multiple Applications Mitochondria are double-membrane bound organelles that contain their own genome (mtDNA), which is organized into nucleoprotein structures, called nucleoids, attached to the inner membrane facing the mitochondrial matrix. Transfer of exogenous mitochondria into cells that contain or lack (ρ0 cells) mtDNA could improve our understanding of ETC function and metabolism, and the interaction between the mitochondrial and nuclear genomes. Mitochondrial transfer also may hold potential for treating diseases of dysfunctional mitochondria caused by mutations in mtDNA. Cell Metabolism 2016 23, 785-796DOI: (10.1016/j.cmet.2016.04.004) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 2 Current Methodologies for Manipulating mtDNA in Mammalian Cells Targeted degradation of endogenous mtDNA to shift heteroplasmy ratios can be performed with mitoTALENs or mitoZFNs. The mtDNA heteroplasmy ratio can also be shifted through a “bottleneck” during the reprogramming of somatic cells to induced pluripotent stem cells (iPSCs). Adeno-associated virus (AAV) transduction can deliver up to ∼5 kbp DNA into mitochondria that does not integrate into the mitochondrial genome. RNA and protein import can potentially compensate for dysfunctional mtDNA gene products. Whole mitochondria transfer technologies focus on delivering either isolated mitochondria (co-culture, microinjection, or photothermal nanoblade) or mitochondria from a donor cell (mitocytoplast or cytoplasmic fusion) to a recipient cell. Importantly, none of these methods can generate novel mtDNA sequences. To generate non-native mtDNA sequences, repair cells with mtDNA disorders, or establish cell lines with unique mtDNA mutations for basic studies and disease modeling, new methods are needed to insert, delete, or substitute sequences into existing mtDNA (reverse genetics). Cell Metabolism 2016 23, 785-796DOI: (10.1016/j.cmet.2016.04.004) Copyright © 2016 Elsevier Inc. Terms and Conditions