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Updated: Aug 9, 2026
An In Vitro Approach to Study Mitochondrial Dysfunction: A Cybrid Model
Published on: March 9, 2022
Development and initial characterization of xenomitochondrial mice
I A Trounce1, M McKenzie, C A Cassar
1Genomic Disorders Research Centre, and Centre for Neuroscience, University of Melbourne, Victoria, Australia.
Abstract:
Xenomitochondrial mice harboring trans-species mitochondria on a Mus musculus domesticus (MD) nuclear background were produced. We created xenomitochondrial ES cell cybrids by fusing Mus spretus (MS), Mus caroli (MC), Mus dunni (Mdu), or Mus pahari (MP) mitochondrial donor cytoplasts and rhodamine 6-G treated CC9.3.1 or PC4 ES cells. The selected donor backgrounds reflected increasing evolutionary divergence from MD mice and the resultant mitochondrial-nuclear mismatch targeted a graded respiratory chain defect. Homoplasmic (MS, MC, Mdu, and MP) and heteroplasmic (MC) cell lines were injected into MD ova, and liveborn chimeric mice were obtained (MS/MD 18 of 87, MC/MD 6 of 46, Mdu/MD 31 of 140, and MP/MD l of 9 founder chimeras, respectively). Seven MS/MD, 1 MC/MD, and 11 Mdu/MD chimeric founder females were mated with wild-type MD males, and 18 of 19 (95%) were fertile. Of fertile females, only one chimeric MS/MD (1% coat color chimerism) and four chimeric Mdu/MD females (80-90% coat color chimerism) produced homoplasmic offspring with low efficiency (7 of 135; 5%). Four male and three female offspring were homoplasmic for the introduced mitochondrial backgrounds. Three male and one female offspring proved viable. Generation of mouse lines using additional female ES cell lineages is underway. We hypothesize that these mice, when crossbred with neurodegenerative-disease mouse models, will show accelerated age-related neuronal loss, because of their suboptimal capacity for oxidative phosphorylation and putatively increased oxidative stress.
Insights
Researchers created xenomitochondrial mice with diverse species mitochondria to study mitochondrial-nuclear interactions. These mice may accelerate neurodegeneration research by modeling oxidative stress and impaired energy production.
Area of Science:
- Mitochondrial biology
- Genetics
- Neuroscience
Background:
- Mitochondrial DNA (mtDNA) plays a crucial role in cellular respiration.
- Mismatches between nuclear and mitochondrial genomes can lead to cellular dysfunction.
- Understanding these interactions is key for studying metabolic and neurodegenerative diseases.
Purpose of the Study:
- To generate xenomitochondrial mice with varying degrees of mitochondrial-nuclear genetic divergence.
- To investigate the impact of mitochondrial-nuclear mismatch on cellular respiration and potential disease modeling.
- To establish a novel mouse model for studying age-related neuronal loss and oxidative stress.
Main Methods:
- Created xenomitochondrial mouse embryonic stem (ES) cell cybrids by fusing cytoplasts from different Mus species with mouse ES cells.
- Injected these cybrids into Mus musculus domesticus (MD) ova to produce chimeric mice.
- Assessed fertility and efficiency of producing homoplasmic offspring with introduced mitochondrial backgrounds.
Main Results:
- Successfully generated chimeric mice with homoplasmic and heteroplasmic xenomitochondria from Mus spretus, Mus caroli, Mus dunni, and Mus pahari.
- Chimeric females demonstrated high fertility rates.
- Production of homoplasmic offspring was inefficient, with limited viable offspring carrying the introduced mitochondrial genomes.
Conclusions:
- Xenomitochondrial mice can be generated, but efficient production of homoplasmic offspring remains a challenge.
- These mice represent a valuable tool for studying the consequences of mitochondrial-nuclear genetic mismatch.
- The model holds promise for investigating accelerated age-related neuronal loss and oxidative stress in neurodegenerative disease research.
