In the field of Biotechnology, the discoveries of modern genetic tools bring advancement day-by-day. CRISPR Cas9 is one of the foremost discoveries in the genetic world.
CRISPR stands for Cluster regulatory interspaced Short palindromic repeats. These are a special kind of DNA sequences that can be found only in the prokaryotic organisms like bacteria. These sequences are used as defense mechanism in bacteria that are attacked by a special kind of virus called bacteriophages.
Cas9: It stands for CRISPR associated protein 9. Cas9 is an enzyme that is used to cleave the complementary strand of CRISPR sequence. Cas9 uses the CRISPR sequence to detect the sequence that is to be cleaved. It was discovered by a scientist Makarova and colleagues. Some Cas protein can cleave the DNA sequences whereas some can cleave RNA sequences. For example, DNA can be cleaved by cas9 and RNA can be cleaved by cas13.
CRISPR and cas9 together form a special technique called CRISPR-Cas9 that is used to modify the genes in a genome of living organisms.This technique is widely used in the field of biotechnology.
A number of scientists/researchers have worked on this technique and published various articles related to this field. The first description about CRISPR was given by a researcher Yoshizumi Ishino and his colleagues from Osaka University in 1987.
CRISPR CAS9 has a very crucial role in building microbial immunity. Naturally this system provides an immunity to the bacteria against the attack of bacteriophages so they are considered as acquired immunity in bacteria.
The use of this technique was highlighted in the year 2012 when a group of scientists used it as a tool to modify some particular region of prokaryotic genome.
It was predicted that the mechanism of this system is same as the process of RNA interference in which cleaving mRNA makes the protein complexes to silence the genes.
This system is also known as DNA editing tool as it can remove, add, modify , silence or activate any sequence in the genome.
In the field of biotechnology, CRISPR-Cas9 system has a very prime role because this tool is not only used as microbial immunity booster but it can also be used to cure various diseases at genetic level.
This tool can be used to cure genetic disorders like sickle cell anaemia and cystic fibrosis. It is also helpful in treatment of cancer and some other infectious diseases.
Modifications in Cas9 nuclease has been done by the researchers to perform the Targeted epigenome editing. The modified Cas9 nuclease is enzymatically dead so known as dcas9. This modified dcas9-enzyme do not cleave the sequence but modify epigenome at the site.
Epigenome editing can help in gene activation and gene silencing.
This tool is very helpful in detection and characterisation of mutations that boosts our understanding of finding special drugs against fatal diseases like cancer and Surveillance of infectious diseases like COVID-19.
As this is a newly discovered tool in modern Biosciences, so many of its uses are undiscovered till now. As sky has no limit maybe application of this tool will have no limits.
Ms. Bipasha Ghosh.
M.Sc. Biotechnology
