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Milestone achieved in mitochondrial genome editing
Researchers at Korea’s Institute for Basic Science (IBS) have developed a new gene-editing platform called transcription activator-like effector-linked deaminases, or TALEDs — base editors capable of performing A-to-G base conversion in mitochondria.
T
editing of living cells. This opened new possibilities
sudden blindness in both eyes, is caused by a simple
for treating previously incurable genetic diseases by
single point mutation in mitochondrial DNA.” Another mitochondrial gene-related disease
editing the mutations out of our genome. However, while gene editing has been largely
includes mitochondrial encephalomyopathy with
he team’s discovery was the culmination
successful in the nuclear genome of the cells,
lactic acidosis and stroke-like episodes (MELAS),
of a decades-long journey to cure human genetic
scientists have been unsuccessful in editing the
which slowly destroys the patient’s brain. Some studies
diseases, and could be considered to be the
mitochondria, which also have their own genome.
even suggest abnormalities in mitochondrial DNA
final missing piece of the puzzle in gene-editing
Mitochondria, the so-called ‘powerhouse of the
may also be responsible for degenerative diseases
technology. It has been published in the journal Cell.
cells’, are tiny organelles in cells that serve as
such as Alzheimer’s disease and muscular dystrophy.
From the identification of the first restriction
energy-generating factories. As it is an important
The mitochondrial genome is inherited from the
enzyme in 1968, to the invention of polymerase chain
organelle for energy metabolism, if the gene is
maternal line. There are 90 known disease-causing
reaction (PCR) in 1985 and the demonstration of
mutated, it causes serious genetic diseases related
point mutations in mitochondrial DNA, which in total
CRISPR-mediated genome editing in 2013, each
to energy metabolism.
affects at least one in 5000 individuals. Many existing
new breakthrough discovery in biotechnology
“There are some extremely nasty hereditary
genome editing tools cannot be used due to limitations
further improved our ability to manipulate DNA,
diseases arising due to defects in mitochondrial
in the method of delivery to mitochondria. For
the blueprint of life. In particular, the recent
DNA,” said Jin-Soo Kim, Director of the IBS Center
example, the CRISPR-Cas platform is not applicable
development of the CRISPR-Cas system, or ‘genetic
for Genome Engineering. “For example, Leber
for editing these mutations in mitochondria, because
scissors’, has allowed for comprehensive genome
hereditary optic neuropathy (LHON), which causes
the guide RNA is unable to enter the organelle itself.
12 | LAB+LIFE SCIENTIST - Jun/Jul 2022
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