CRISPR-Cas9 gene editing technique

CRSPR-Cas9 technology is a famous gene editing technique. This technology is used to cut the target DNA at a specific site and after that the gene can be left totally destroyed or can be altered because of the body’s natural repair mechanism. Because, The repair mechanism is prone to errors and may induce mutations or alter the genome.

The basis of this technology resides in the bacterial Immunity. Bacterias get infected by the phages. And the phage DNA gets fused to the bacterial genome as natural process. If the bacteria survives the attack, the fused genome forms CRISPR or clustered regularly interspaced short palindromic repeats. Transcription will produce CRISPR-RNA which can bind to the phage genome because it is complementary to that. Cas9 is a protein type called nuclease which has the capacity to cleave the nucleotide strand, that is DNA and also can be easily programmed to bind to any target sequence. The combination of CRISPR-RNA and cas9 act as a certain type of memory which helps the bacteria to kill the phage if it attacks again. The CRISPR-RNA binds to the phage genome, and the cas9 cuts it, making sure that the phage will be destroyed.

The same procedure is used to edit the genomes of other species. The procedure of CRISPR-Cas9 first involves the production of CRISPR-RNA which is complementary to the target site. The combination of the CRISPR-RNA and cas9 protein is introduced into the cell. Both cas9 and CRISPR-RNA are programmed to bind to the target site. Once the RNA binds to the target site, the Cas9 protein gets activated. Now, there are sites on the genome called PAM sites. Cas9 protein cleaves DNA at this specific PAM sites on both the strands. Now bodies natural repair mechanism tries to repair the cleaved site. During this process some mutations can happen or alteration in the genome can happen. This alteration may result in the deactivation of the entire gene, or changes in the products of that gene.

Not only gene editing, CRISPR-Cas9 can also be used to do selective transcription where only selected part of the gene is transcribed. It can also be used to inhibit the same. This technique can also be used to marking or live imaging of the target gene. All these can be done by just deactivating the cas9 protein.

disease control with crispr technology
  • This technology can be used to treat cancer by modifying the immune T cells of the patient.
  • It can also be used to treat beta-thalassemia, a blood disorder by editing the bone marrow cells of the patient to produce hemoglobin.
  • It can also be used to treat blindness by editing a single gene causing the problem.
  • It can also be used to treat cystic fibrosis by treating the CFTR genes.

crispr gene editing in space

NASA astronauts have performed first in space CRISPR gene editing, They used this technology to modify the yeast genome as if it mimics the damage caused by the radiation. This will help to study the damages to human body in space and the ways to prevent them. The idea is first proposed by students named David Li, Arthi vijaykumar, Rebecca Li and Michelle Sung in Genes in space contest. Christiana Koch and Nick Hauge carried out this experiment.

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