PROJECT 2 – CRISPR-cas9
Genetic “cut and paste”
Chosen as “Breakthrough of the Year” by Science Magazine in 2015, a genetic engineering technology called CRISPR-cas9 is derived from a bacterial defence mechanism. This new technique for targeted genome editing has spread like wildfire to laboratories everywhere.
CRISPR-cas9 is, by far, the most effective technique to correct DNA defects. Described as a “molecular toolkit,” this clever and complex technique enables researchers to perform “cut and paste” operations on DNA.
This technology works as follows:
- CRISPR is a type of gene sequence found naturally in specific organisms, including viruses. It can recognize a particular DNA sequence, i.e., find the place on a DNA strand where a disease-causing genetic defect (mutation) lies.
- Cas9 acts like a pair of scissors. It “cuts” DNA at a specific location, i.e., where an action is needed to repair or eliminate a genetic defect.
- With this technology, researchers can remove a genetic mutation or insert a fix for a faulty gene sequence.
- Using normal DNA repair mechanisms, the cell will then naturally reattach the severed DNA strands.
An encouraging step in the fight against DMD
Duchenne muscular dystrophy (DMD) results from an error in the “writing” of the dystrophin gene. In children with DMD, the dystrophin gene is corrupt – it contains a genetic defect (mutation). The gene is so badly “written” that the cellular machinery cannot accurately “read” the genetic instructions to produce dystrophin – a protein that’s essential for proper neuromuscular function.
Researchers are using CRISPR-cas9 to remove the corrupt part of the genes (mutations). “Erasing” problem areas on a DNA strand may restore accurate protein decoding. With this technology, DMD researchers have been able to restore the production of dystrophin.
Researchers have found a way to transport this molecular toolkit aboard viruses with a particular attraction to muscle cells. They injected this mixture into mice models that could not synthesize dystrophin. After a few weeks, the rodents’ muscles began to produce dystrophin.
A brilliant idea, to say the least!
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