CRISPR-Cas9 is a gene-editingtechnology that has been continually improved since its creation.
Thistechnology can be used to prevent and treat various genetic diseases. Recently,scientists have developed a new and effective way to deliver this technologyinside cells. By using gold particles to deliver new genetic material to acell, these scientists have modified and improved the CRISPR-Cas9 mechanism. Today, CRISPR-Cas9 is the simplestand most precise method of gene editing that is available to medicalresearchers and geneticists. In order for CRISPR to modify DNA, Cas9, an enzymethat cuts the DNA at a certain location, donor DNA and a piece of guide RNA(gRNA) are needed. The gRNA locates and binds to a certain sequence within theDNA and guides the Cas9 enzyme to that section. Once in the proper section ofDNA, the Cas9 then cuts both strands of the double stranded DNA in the correctplace.
This causes the cell to begin to repair the DNA that has just beendamaged through homology-directed DNA repair. The cell uses the donor DNA thatis provided to it and mends the DNA. There are problems with CRISPR-Cas9 inregard to its safe delivery of the essentials for gene editing into the cell. CRISPR-Cas9often uses viruses to deliver genetic material into a cell.
This has obviouscomplications and risks that come along with it. One example is the use ofretroviruses as vectors to deliver genetic information into the T-cells of apatient in order to kill cancer. This is a problem because if the geneticinformation is not properly delivered, that patient’s cells will attack eachother and the patient will die. It has often been noted that the mistakes thatare made by CRISPR-Cas9 are results of a delivery malfunction. In order to fix the delivery issue,researchers at the University of California, Berkeley, have created a vesselfor the necessary genetic information.
CRISPR-Gold, as it has been cleverlynamed, does not utilize viruses but instead uses gold particles to transportCas9, gRNA, and donor DNA into the living cells of an organism. The goldparticles that form the vessel bind all of the gene-editing components togetherand, once inside whatever cell has been targeted, releases them in order totrigger homology directed repair. Once injected into an organism, the cells ofthat organism recognize a marker within the CRISPR-gold and transport thedelivery receptacle into the cell where it releases the Cas9 enzyme and thedonor DNA. In the study that Niren Murthy andIrina Conboy performed, the CRISPR-Gold mechanism’s performance was evaluatedin mice with Duchenne muscular dystrophy. A single injection of thisCRISPR-Gold technology restored 5.
4% of the gene that codes for the disease tothe wildtype sequence. The mice treated with the Cas9 and donor DNA without thegold particle shield only experiences a 0.3% correction rate.
Comparatively, itis clear that the gold particle vessel makes the CRISPR technology much moreeffective. In fact, within the study on the mice with muscular dystrophy, theCRISPR-Gold mechanism had a correction rate that was 18 times higher than thetrial without the gold particles. In conclusion, the CRISPR-Cas9gene-editing technology has been constantly improving since its initial debut.
The most recent advancement, a vessel made from gold particles, has been to bea safer and more effective method of transporting genetic information into atarget cell than the common method of using a virus. With this new advancement,this technology is one step closer to becoming a common, effective and safe wayof treating genetic diseases within the human population.