In less than a decade, CRISPR has become the go-to method for gene editing. For the most part, scientists have only been able to edit a few genes at a time. CRISPR has shown promise in treating diseases like cancer and AIDS, but only being able to edit one or two genes has held the science back. This restriction is due to the myriad of ways that genes interact with one another.
Now, a new breakthrough in the gene-editing method from a Swiss team at ETH Zurich in Basel has shown for the first time ever that simultaneous multiple gene editing is possible, according to reports from New Atlas. Being able to edit more genes will, in turn, allow for large-scale cell reprogramming, thus increasing the chances of curing more afflictions.
The ETH Zurich team published their findings in the journal Nature Methods. Their paper details how the new CRISPR process can alter 25 distinct target sites simultaneously. However, the group noted that the new gene-editing method can go beyond 25 genes and is scalable to hundreds of modifications.
Cas12a All Day
The team accomplished this feat by looking beyond the traditional Cas9 enzyme used in most CRISPR editing. Instead, the researchers turned to the lesser-known Cas12a enzyme. This version has proved more precise in locating targeted genes. The ETH Zurich team discovered that Cas12a can also work with shorter RNA address molecules than Cas9.
Being able to read these shorter RNA sequences is key. The traditional CRISPR-Cas9 system finds its target DNA by utilizing a pre-designed RNA sequence dubbed “guide RNA.” In other words, the RNA sequence works like a GPS and guides CRISPR to the correct DNA address.
The team’s innovative new method entails the creation of a circular DNA molecule, known as a plasmid, that can hold a number of RNA addresses. The shorter the RNA address, the more a plasmid can hold. This is where Cas12a shines as it is more adept at reading shorter RNA sequences than its Cas9 cousin.
A Genetic Dream Come True
For Randall Platt of ETH Zurich in Basel’s Department of Biosystems Science and Engineering, the breakthrough is a dream come true. “Thanks to this new tool, we and other scientists can now achieve what we could only dream of doing in the past,” he said in a statement. “Our method enables us, for the first time, to systematically modify entire gene networks in a single step.”
Platt and his team’s achievement is impressive. When scientists tackle a disorder caused by problems in just one gene, single-gene editing works fine. However, many (and indeed most) conditions exhibit a much more complicated gene scenario.
The breakthrough from the ETH Zurich will allow scientists to map wider genetic interactions. It will also provide treatments, and hopefully cures, to countless patients around the world.