The 2020 Nobel Prize in Chemistry has been awarded to Emmanuelle Charpentier and Jennifer A. Doudna for the discovery of the CRISPR/Cas9 gene editing tool.
CRISPR, an acronym of Clustered Regularly Interspaced Short Palindromic Repeats, is a form of “genetic scissors” which uses an enzyme – in this case Cas9, although there are several – to cut DNA and make edits, either the removal of a defective gene, insertion of a functional gene, or the correction of a mutation.
CRISPR-Cas9 is a defense mechanism that has been used by bacteria and archaea for millions of years as a defense against viruses. When a virus enters a bacterium, a “mug shot” is taken of the virus and it is inserted between the repeats. When the bacteria next encounters the virus, RNA copies of the mug shots are made, which work with another RNA called trans-activating CRISPR RNA (tracrRNA) to form a guide RNA (gRNA). The gRNA guides the Cas9 enzyme to the virus. The enzyme then performs a cut and eliminates the virus.
Emmanuelle Charpentier, a microbiologist and director of the Max Planck Unit for the Science of Pathogens, discovered a previously unknown molecule in bacteria – tracrRNA – almost a decade ago. Investigation of that molecule revealed it was part of a bacterial immune system to combat viruses.
Jennifer A. Doudna, a University of California, Berkeley professor and biochemist, was researching cas enzymes in bacteria around the same time. The two started collaborating in 2011 after discovering their work overlapped and succeeded in creating programmable genetic scissors in the lab which they used to make cuts to DNA at whatever location they chose.
CRISPR-Cas9 is now used by researchers to make genetic changes to crops to make them hardy to drought and withstand pests and bacteria. The CRISPR system is used extensively by researchers to correct mutations and replace defective genes, including in human cells. Several clinical trials are now underway that use CRISPR-Cas9 in novel cancer therapies and to correct mutations that cause a range of inherited diseases. The CRISPR-Cas9 gene editing tool has since been tweaked by researchers to allow it to be used in many different ways. The tool is inexpensive, efficient, accurate, and incredibly versatile, and has been instrumental in many breakthroughs and advances over the years.
Only 5 women have ever been awarded the Nobel Prize in Chemistry and this is the first time that the prize has been shared by two women. Charpentier and Doudna will share the $10 million Swedish kronor ($1.1 million) prize money.
The paper published by the researchers – A Programmable Dual-RNA–Guided DNA Endonuclease in Adaptive Bacterial Immunity – in Science in 2012 has been cited more than 9,500 times since publication.