CRISPR - THE FUTURE OF GENE EDITING TECHNOLOGY
Recently two of the world-renowned scientists namely Emmanuelle Charpentier and Jennifer Doudna were awarded the Nobel Prize in Chemistry for pioneering the CRISPR gene-editing technique.
The CRISPR or Cas9 as it is said isn’t a very recent technology but there for a few years now.
From curing
numerous life-threatening diseases and many changes in the gene to treating
COVID affected patients, this technology has grown so much that scientists are
thinking of using as a means of stopping climate change.
What is CRISPR?
CRISPR (clustered regularly interspaced short palindromic repeats) is a family of DNA sequences found in the genomes of prokaryotic organisms such as bacteria and archaea.
They are used to detect and destroy DNA from similar bacteriophages during subsequent infections. Hence these sequences play a key role in the antiviral defense system of prokaryotes.
In simple words, it is a powerful tool for genome editing. This technology allows researchers to easily alter DNA sequences and modify gene function. "CRISPR" (pronounced "crisper") is shorthand for "CRISPR-Cas9." which is specialized stretches of DNA.
The protein Cas9 is an enzyme that acts like a pair of molecular scissors, capable of cutting strands of DNA. Since the CRISPR is derived from bacteria and archaea, so these organisms use CRISPR-derived RNA and various Cas proteins, including Cas9, to foil attacks by viruses and other foreign bodies. They do so primarily by chopping up and destroying the DNA of a foreign invader.
Researchers have been playing
with CRISPR for years, tackling HIV, deleting genetic diseases from the cells of experimental human embryos, and
raising the possibility of cross-species organ
transplants. Some scientists are even seriously talking about resurrecting the
long-extinct woolly mammoth with CRISPR's help.
Benefits of CRISPR
It corrects genetic disorders
Hypertrophic cardiomyopathy (HCM) is a heart condition that affects roughly 1 in every 500 people worldwide. Its symptoms are painful and often deadly. Thanks to recent medical advances, the average life expectancy of someone with HCM is close to that of the general population, but the condition can lead to life-threatening situations if left untreated.
In summer 2017, scientists at Oregon Health and Science University used CRISPR to delete one of these defective genes in several viable human embryos.
The results were promising: Of the 54 embryos
that were injected with the CRISPR-Cas9 machinery 18 hours after fertilization,
36 did not show any mutations in the gene (practically no chance of developing
the disease) and 13 were partially free of mutations (with a 50 percent chance
of inheriting HCM).
Helps in the elimination of microbes
In 2017, a team of Chinese researchers successfully increased resistance to HIV in mice by replicating a mutation of a gene that effectively prevents the virus from entering cells.
In a slightly different approach, scientists in North Carolina used CRISPR to engineer bacteriophages, a type of virus that infects and duplicates itself inside a bacterium, to kill harmful bacteria.
It can resurrect extinct species
In February 2017, Harvard geneticist George Church made
a surprising announcement before the annual meeting of the American
Association for the Advancement of Science. He claimed his team was just two
years away from developing an embryo for an elephant-mammoth hybrid.
It will help in the creation of new nutritious foods
Scientists from Cold Spring Harbor Laboratory in New York used the tool to increase the yield of tomato plants. Traditional GMOs are made by inserting foreign DNA sequences into a crop’s genome, transmitting traits or properties to future organisms.
Gene editing is more
precise than that: it makes precise alterations to genes in specific locations
of the native genome, often knocking out certain genes or changing their
location, all without introducing foreign DNA.
It could eradicate dangerous disease-spreading pests
Scientists at the University of California, Riverside developed a kind of mosquito that is uniquely susceptible to changes made with CRISPR, giving scientists unprecedented control over the traits that the organism passes to its offspring.
By disrupting target genes in multiple locations of the mosquito’s genes, the team is testing a “gene drive” system to spread these inhibiting properties.
By impairing the mosquito’s flight
and vision, the Riverside team is hoping to greatly reduce its ability to
spread dangerous infectious diseases among humans, such as dengue and yellow
fever.
Beyond CRISPR - Genome editing
Genome editing technologies enable scientists to make changes to DNA, leading to changes in physical traits, like eye color, and disease risk.
Scientists use different technologies to do this. These technologies act like scissors, cutting the DNA at a specific spot. Then scientists can remove, add, or replace the DNA where it was cut.
CRISPR is simpler, faster, cheaper, and more accurate than older genome editing methods. Many scientists who perform genome editing now use CRISPR. Even though CRISPR improved upon older genome editing technologies, it is not perfect.
For example, sometimes genome editing tools cut in the wrong spot. Scientists are not yet sure how these errors might affect patients. Scientists are developing gene therapies - treatments involving genome editing - to prevent and treat diseases in humans.
Genome editing tools have the potential to help treat diseases with a genomic basis, like cystic fibrosis and diabetes.
In
2015, scientists successfully used somatic gene therapy when a one-year-old in the United
Kingdom named Layla received a gene-editing treatment to help her fight
leukemia, a type of cancer. These scientists did not use CRISPR to treat Layla,
and instead used another genome editing technology called TALENs.
CRISPR related Researches
- In April 2017, a team of researchers released research in the journal Science that they had programmed a CRISPR molecule to find strains of viruses, such as Zika, in blood serum, urine, and saliva.
- On Aug. 2, 2017, scientists revealed in the journal Nature that they had removed a heart disease defect in an embryo successfully using CRISPR.
- On Jan. 2, 2018, researchers announced that they may be able to stop fungi and other problems that threaten chocolate production using CRISPR to make the plants more resistant to disease.
- On April 16, 2018, researchers upgraded CRISPR to edit thousands of genes at once, according to research published by the journal Bio News.
Conclusion
Current scientific advancements show that CRISPR is not only an extremely versatile technology, but it’s also proving to be precise and increasingly safe to use.
But a lot of progress still has to be made; we are only beginning to see the full potential of genome-editing tools like CRISPR-Cas9. The rapid progress in developing Cas9 into a set of tools for cell and molecular biology research has been remarkable.
Of the designer nuclease systems currently available for precision genome engineering, the CRISPR/Cas9 system is by far the most user friendly.
Even though technical hurdles bind us from a future where we feed the planet with engineered food, eliminate genetic disorders, or bring extinct animal species back to life. But the destination is not very far and are thus on our way to success.
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CRISPR technology looks good, though you have made a valid point, if the gene is cut wrongly, none knows the effect on the patient. But this technology give hope to many patients, who are born with big genetic disorders.
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