CRISPR- Clustered Regularly Interspaced Short Palindromic Repeats-is one of the hottest topics in discussion in the world of
molecular biology and genetic engineering now days. A phenomenon once
discovered to be as bacteria’s immunity against several types of phage viruses
has now become the most important weapon in science’s arsenal to deal with a
wide range of problems faced by the mankind. The CRISPR has become the most
important tool of the genetic engineering tool box to deal with and to solve
many challenges faced in the world of science. CRISPR is a molecular gene
editing tools used to alter, delete and create a new genetic sequence or a new
genetic combination in an organism’s genome.
History:
- CRISPR was first discovered in 1987 by Youshizumi Ishinu at the Osaka University. He discovered these sequences in the bacterial genome when he accidently cloned a part of CRISPR sequence while working on the “iap” gene.
- Later in the 1990’s meta-genomic sequencing approach unveiled many things about this newly discovered sequence as hundreds of thousands samples were collected and tested.
- In 1993 researchers from Netherlands reported about existence of several genetic repeats in Mycobacterium tuberculosis.
- In the same year microbiologists Francisco Mojica observed similar repeats in 2 different archaea and by 2000 his team identified these repeats in 20 different kinds of microbes.
- In 2001 Francisco Mojica and Ruud Jansen proposed the term CRISPR for these repeats. Later Rudd Jansen and his team identified cas genes.
- In 2009 the most important discovery in the world of CRISPR came the formation of guide RNA(gRNA) in a CRISPR/CAS-9 system. This was done by Jennifer Doudna (UK) and Emmanuel Charpentier (France). For the first time ever scientists were able to alter the CRISPR/CAS-9 system to their will. This discovery was like a new hope of light in the world of science, as this discovery removed many obstacles in the path of research and paved path for scientists which would ultimately lead to new discoveries.
- In 2015 an entirely new CRISPR system the CRISPR/CPF-1 was discovered which in many ways is more efficient than the CRISPR/CAS-9 system.
How it
Works:
Originally CRISPR was discovered as bacteria’s natural immune
system which enables them to fight and overcome the invading viral infection,
whenever a viral Genome enters in to the bacterial cell the CRISPR sequence of
bacterial genome is turned on, the CRISPR sequence is composed of three main
components CAS gene which encodes for CAS protein (an endonuleases),
Palindromic repeats which codes for TracrRNA and the Spacer DNA which codes for
CrRNA, the spacer DNA itself is the copy of viral genome which attacks the
bacteria, bacteria forms a copy of that viral genome and stores it so whenever
that virus or a closely related virus attacks again the bacteria produces CrRNA
using the viral genome copy, load it inside the CAS protein and match it with
genome of invading virus if there is a match the bacterial encoded CAS protein
immediately cuts and denatures the viral genome. .At first it was believed that
the CRISPR/CAS-9 system cannot be used for human betterment because of its
complexity but two scientists proved it wrong, Jennifer Doudna and Emmanuel
Charpentier, in 2009 these two dealt with the complexity of CAS-9, First
combining the TracrRNA and CrRNA to form a single Guide RNA and secondly
showing that The Guide RNA can be altered according to our own will, So
ultimately it can be used for betterment of mankind in many ways.
Achievements
of CRISPR:
Today CRISPR is being used in many fields of life sciences to
resolve ever increasing problems faced by mankind. This synthetic gene editing
technology is helping us in solving many of our problems and is completely
revolutionizing the world of science. The CRISPR technology enables us to cut,
alter and create new genetic combinations. So far many great things have been
achieved using this gene editing technology.
- Dealing with HIV is perhaps one of the biggest achievements. HIV virus causes AIDS one of the most devastating human disease, as its victim’s immune system fails to defend the body against invading pathogens. In may 2017 scientists reported in Molecular Therapy they have successfully prevented HIV infection in different model animals injected with human cells.
- Scientist reported to have created a cancer destroying genetic combination which resulted in shrinkage of cancer cells in mice which was injected with human prostate and liver cancer cells.
- Researchers have also started to alter human embryo gene in order to stop various genetic transmitted disorders. Scientists have reported to successfully remove MYBPC3 gene from a human embryo. This MYBPC3 gene is responsible for causing Hypertrophic Cardiomyopthy.
- Scientists also altered algae enabling them to produce bio-fuels twice the amount as compared to natural counterparts.
- CRISPR technology is also turning out in to a success in dealing problems with transgenic plants. Transgenic or genetically engineered plants are banned in the entire EU but CRISPR technology is proving out to be an exception as the Swedish Agriculture Board reported that CRISPR edited plant does not fall under the GMO definition as no foreign DNA is being added inside plant.
- CRISPR edited mushrooms also succeeded in escaping the USDA’S GMO regulation.
- CRISPR technology also helps in making plants resistant to various pathogens. A group of Chinese Scientist reported to have successfully developing resistance in wheat plant against powdery mildew disease using CRISPR technology.
Leading
Countries in CRISPR Research:
CRISPR has probably
become the most important topic to discuss and research in the field of life
sciences now days, with advanced countries heavily investing in it. But some
are outperforming almost everyone.
- Together USA, China, Germany, and Japan are responsible for more than 62% CRISPR publications in the world over the last five years. With USA leading the way with 1108 publications, right after the US is China with 351, Germany at third with 206 and Japan at number four with 176 publications.
- The over-all scholarly output of US alone has increased by an average 254%.
- The total number of citations received by Japanese researchers has increased by 1031%.
CONCLUSION:
In the end it's a
simple conclusion that CRISPR/CAS-9 is a gift of nature for mankind to deal
with its problems.
