Gene-editing Tool - CRISPR

- Overview

CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats. It is a component of the bacterial immune system that cuts DNA and has been repurposed as a gene-editing tool. It acts as a pair of precise molecular scissors that can cut target DNA sequences, guided by customizable guides. 

The system consists of two key parts: a CRISPR-associated (Cas) nuclease that binds and cuts DNA, and a guide RNA sequence (gRNA) that guides the Cas nuclease to its target. It is found in the bacterial immune system, which cuts the DNA of invading viruses, called phages, and disables them. Once the molecular mechanism of its DNA-cutting ability was discovered, it was rapidly developed as a genome editing tool. 

CRISPR is important because it allows scientists to rewrite the genetic code of almost any organism. It is simpler, cheaper and more precise than previous gene editing techniques. In addition, it has a range of practical applications, including the treatment of genetic diseases and the cultivation of drought-resistant crops.

- How CRISPR Works

CRISPR enables researchers to cut and paste DNA sequences. First, scientists compose a string of genetic letters, or "guide RNAs," like those original viral code fragments that can identify specific stretches of DNA among the billions of As, Ts, Gs, and Cs in the genome. 

Second, they introduced this guide sequence into target cells along with an enzyme like Cas9, which recognizes matching text and cuts it open. Scientists use this mechanism to delete, mutate, insert or repair genomic DNA sequences in cells, animals and humans. 

Since the technology was developed in 2012, more than 8,000 scientific papers mentioning CRISPR have been published. Today, research laboratories in more than 80 countries use it to study the molecular basis of disease and develop new treatments.

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