What is CRISPR-Cas9 Technology ?
CRISPR-Cas9 is a gene editing technology that was discovered a few years ago. This technology was discovered by scientists while working on the mechanism of how bacteria fight against viral infections. Most of the bacteria have adaptive immune system by which the bacteria can identify and destroy the nucleic acid molecules of viruses and thus inhibit the infection of viruses. Basically, this system is known as CRISPR.
The Cas9 is a protein of the CRISPR-Cas9 system. This protein can detect and dissect the viral DNA or RNA. How this mechanism works is identified by the scientists and they have also found out how to use this technology in the field of genetic engineering. Using this technology, the scientists can delete, insert or modify a specific portion of the gene. That's why, CRISPR-Cas9 is also called a gene editing tool.
The mechanism behind CRISPR-Cas9 Technology
When a virus attacks a cell, it injects it's DNA or RNA into the cell. The bacterium responses to this attack by cutting the viral DNA or RNA in small pieces and integrating those pieces into it's own DNA. The regions where these pieces are added are called 'Clustered Regularly Interspaced Short Palindromic Repeats' or 'CRISPR'.
Now, this integration helps the bacterium to keep record of which virus has already attacked them and build up a memory against that particular type of virus for over many generations. So, if the same virus again attacks in the future, then the bacteria can defend itself from the viral attack by activating it's adaptive immune responses.
When, the integrated pieces of viral nucleic acid is expressed from the bacterial DNA, they produce mRNA molecules that are complementary to the infecting viral nucleic acids. Once the complementary sequences found each other, they hybridize with each other and thus the expressed mRNA can shut of the viral gene. Cas9 protein helps the mRNA to shut down the gene.
This method can be used in combination with computer to remove specific DNA sequences in any type cell to silence the genes. That's how the CRISPR-Cas9 technology works.
A representation of how this system is utilized in genetic engineering, is given in the picture below:
Some recent advances and applications :
Using this revolutionary technique, a group of scientists in China was about 48% successful in inhibiting the replication of HIV virus. And recently, they are trying to find ways of how to increase this efficiency.
In 2016, the USA authority has given the permission to carry out this technology in combating various genetic diseases. Using this technology, any defective gene can be identified and edited in such a way that will express the correct normal protein. In Europe, 19% abortions are done due to the early screening of various genetic diseases in the foetus. Using CRISPR-Cas9, the genes responsible for horrible diseases can be identified and treated even before the birth of a diseased child.
CRISPR technology is widely used in cancer research and treatment. Scientists are now trying to identify and modify the faulty genes that cause breast cancer, anemia, blood cancers etc. using CRISPR technology. Thus in the fields of gene therapy and cancer therapy, this technology is playing a major role.
According to a paper published in the scientific journal 'Nature', this technology has paved the way of treating the embryonic Hypertropic Cardiomyopathy.
Moreover, this technique are also used in developing various GMO food that have more nutrient content, better taste and adaptability, lower allergen content.
We all know that, antibiotic resistance is becoming a major crisis in the world. CRISPR-Cas9 can be a solution to combat with this crisis.
© 2019 Bishajit Sarkar