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OK, in mice, but promising for all that.


From The Scientist

Erasing Mitochondrial Mutations
Researchers develop a method to selectively remove mutated mitochondrial DNA from the murine germline and single-celled mouse embryos.

By Jenny Rood | April 23, 2015

Mutations in mitochondrial DNA (mtDNA) can be specifically targeted and removed by transcription activator-like effector nucleases (TALENs) in murine oocytes, single-celled mouse embryos, and fused human-mouse hybrid cells, providing proof of principle for a method that could one day be used to treat certain hereditary mitochondrial disorders in people, according to a study published today (April 23) in Cell.

“It’s an extremely important step,” said Valerio Carelli of the University of Bologna, Italy. “The results are very relevant and very convincing.”

Between 1,000 and 100,000 mitochondria power each human cell. Often, mitochondria in the same cell have different genomes, or haplotypes, a condition known as heteroplasmy. Certain haplotypes include mutations that impact mitochondrial function and cause disease, particularly in energy-hungry organs such as the brain and heart. Because mitochondria segregate randomly as cells divide, it is impossible to determine early in embryonic development how a mix of wild-type and mutated mitochondria inherited from the mother will affect an organism.

To rid mitochondria of these harmful mutations, researchers have used restriction enzymes as well as zinc-finger nucleases (ZFNs) and TALENs, which can be designed to recognize any DNA sequence, to cut and eliminate mutated mitochondrial genomes from heteroplasmic cells.
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