Researchers at the Center for Genome Engineering elaborated what is the smallest Gene Editing tool to date. This editing tool was injected into the eyes of mice and utilized it to modify a gene producing blindness. CRISPR-CAS9 is a pioneering, low cost and effective technique to edit genes. This genetic tool makes cuts in genes like a scissor does to paper. Although, there are other versions of CRISPR-CAS9, the most recent one has 984 aminoacids, making it more adaptable into adeno-associated viruses (AAV).


This is a gene editing system that bacteria use to protect themselves from pathogens, in a similar way that the immune system in humans protects the body from foreign invaders.

Scientists are using the technique to edit genomes by delivering CAS9 into a cell via AAV. The cell´s genome can be modified at the target location, permitting to remove existing genes and add new ones. This gene editing technique has many potential applications in the realm of agriculture and medicine.

C. jejuni CAs9 gene editing scissor

One version of this technique utilizes CAS-9 from the bacterium Streptococcus pyro genes; nevertheless, this protein comprises 1,368 aminoacids making it too large to fit into AAV and less effective. Staphylococcus aureus CAS9 contains 1,053 aminoacids and can be placed inside the AAV, leaving little space for other proteins. C. jejuni CAS9 is the most recent version of DNA editing proteins and has proved more efficient due to its small size-only 984 aminoacids.

It can be inserted into a cell with both; a guide RNA and a fluorescent reporter protein.

Technique used to treat blindness

Scientists introduced CAs9 into AAV and two guide RANs, along with a fluorescent reporter protein. The packed gene editing tool was used to edit genes of mice´s muscles and eyes. The targets were two genes producing macular degeneration due to age (AMD), which causes blindness in adults.

One of the genes is therapeutically known as Vascular endothelial factor A (VEGF A) and the other is a transcription factor known as HIF-1a. The technique proved to be effective at inactivating the two genes in mice, reducing the blindness disorder.