CRISPR-Cas9; The Powerful Gene Editor

As we clearly know that our body is an engine made up of complex materials that works day and night to keep us alive. Though we cannot see many of them from our naked eyes, we can feel them every single second of our life. With the advancement of Science & Technology, we have discovered so various new facts about the mechanism that our body undergoes every second of our life.

We all know very well that our body is simply a pile of various types of hundreds of thousands of cells; all of them having specific types of functions and roles. Our cell is a complex materials made up of DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid) which makes up our genetic structure. And, we all know that our body has a various layer of immune system with various roles and responsibilities but at some point of life we get diseased and eventually has to die.

From infectious to chronic illness our body cells is the key player to win or loose. Upon getting contracted with infectious diseases caused by pathogens such as viruses, bacteria and other parasites our body's immune system gets defeated and depleted leading to the life threatening infection. In the order side, we get chronic diseases such as cancer through the mutation and uncontrolled growth of our body cell causing the tumor and inflammation leading to death. And, our immune system alone cannot defeat the mutating pathogens and cancel cells.

But we have a good news coming that the scientists have discovered the powerful gene editing DNA called CRISPER-Cas9 which can be effectively used to alter the gene of infection causing viruses, our own immune cells and cancel cells. Researchers studied a simpler CRISPR system from Streptococcus pathogen that relies on the protein Cas9. The Cas9 endonuclease is a four-component system that includes two small crRNA molecules and trans-activating CRISPR RNA (tracrRNA).

Jennifer Doudna and Emmanuelle Charpentier re-engineered the Cas9 endonuclease into a more manageable two-component system by fusing the two RNA molecules into a "single-guide RNA" that, when combined with Cas9, could find and cut the DNA target specified by the guide RNA. By manipulating the nucleotide sequence of the guide RNA, the artificial Cas9 system could be programmed to target any DNA sequence for cleavage.

So, how does a CRISPER-Cas9 works?

We should simply understand the CRISPER-Cas9 as the combination of custom made piece of RNA and an enzyme known as Cas9. Then the RNA is engineered to recognize a certain segment of DNA, which further guides the CRISPER-Cas9 system to that section so it can cut, delete and replace the faulty genome with altered version. In the term of Bio-science it is also known as genome engineering.

How can it be used against infectious and chronic diseases?

We can select and clinically modify the immune cells through CRISPER system. And, once our immune system gets attacked by those pathogen our cell will produce two RNA one of which contains the sequence of that matching with the invading pathogen. The two RNAs form a complex with a protein called cas9 which is a nucleus a type of enzyme that can cut DNA.

When the matching sequence understood as the guide RNA find its target within the genome of pathogen, the cas9 simply cuts the target DNA using its two tiny molecular scissors disabling the pathogen. And, this can be done to cure chronic illness such as cancer by simply changing its guide RNA with the DNA sequence of cancerous cell.