CRISPR-Cas9: Crafting Codes

Clustered regularly interspaced palindromic repeats - CRISPR Cas9 is a gene editing technology with growing popularity in biomedical and genomic research. It has the ability to correct errors in the genome, disable certain genes and viruses and cause mutations to inhibit the growth of undesired genes. Having already shown positive results in repairing defecting DNA of mice, it shows great promise in human genetics and clinical applications.

Mechanism of CRISPR-Cas9

It acts as a precise pair of molecular scissors that can cut a target DNA sequence, directed by a customizable guide RNA. The system has two main parts, a guide RNA which directs the Cas9 nuclease to its path and the Cas9 protein nuclease which binds and cuts the DNA. The system was derived from a bacterial immune system where it cuts the DNA of the invading virus and causes mutations in the cut genes, and disables it.  Since the discovery of its cleaving mechanism it is now being studied for various clinical applications.

Genetic disorders like cystic fibrosis can be cured using this technology, the mutations in adult intensional stem cells can be corrected and the CF transmembrane conductor receptor can be restored. It can also be used for treatment of haemoglobinopathies by inducing fetal hemoglobin in patients with sickle cell anemia and thalassemia.

Another potential clinical application of the CRISPR/Cas 9 mechanism is to treat HIV for which no current cure exists due to the permanent integration of thugs virus in the host genome. However the CRISPR system could target the HIV-1 genome activity, subdue its expression, cause mutations and inadvertently disable the virus. 

Although CRISPR/Cas9 technology is the near future of genomics, a large number of ethical and practice challenges must be overcome before it can be practiced at large.