By borrowing a tool from bacteria that infect plants, scientists have developed a new approach to eliminate mutated DNA inside mitochondria—the energy factories within cells. Doctors might someday use the approach to treat a variety of mitochondrial diseases, including the degenerative eye disease Leber hereditary optic neuropathy (LHON). The research, published online today in Nature Medicine, was funded by the National Eye Institute (NEI), a part of the National Institutes of Health (NIH).
Mitochondria convert fuel from food into a form of energy that cells can use. They also make enzymes for a variety of cell functions, and in humans they are the only cell component other than the nucleus that houses genes. Mitochondrial gene mutations can lead to a variety of health problems including muscle weakness, heart disease, and blindness in the case of LHON. Most cells contain thousands of mitochondrial DNA (mtDNA) copies. People with mitochondrial disease often have both mutant and normal mtDNA within their cells. No cures exist for mitochondrial diseases and few effective treatments are available.
Searching for strategies to repair mitochondrial gene defects, a group of investigators at the University of Miami Miller School of Medicine explored proteins called transcription activator-like (TAL) effectors. In nature, TAL effectors are found only in certain types of plant-infecting bacteria. They enable the bacteria to use plant DNA to multiply and spread infection.