CRISPR-Cas originally arose as a natural defence mechanism used by bacteria against invading viruses. In 2012, molecular biologists Emmanuelle Charpentier and Jennifer Doudna used it to invent a new method of modifying DNA building blocks in the genome. Although CRISPR-Cas comes from bacteria, it can be used as a ‘gene scissors’ in almost all organisms. They received a Nobel Prize for this in 2020. The ‘gene scissors’ can be programmed to find a specific location in the DNA and modify the genetic information with pinpoint accuracy.

If you want to transport Cas proteins to the right cells in the body, their size becomes a problem. That is why current studies have attempted to use their much smaller evolutionary precursors as genome editing tools. However, this approach lost efficiency and accuracy.

The research team led by Gerald Schwank from the Institute of Pharmacology and Toxicology at the University of Zurich (UZH) optimised the protein TnpB (a CAS12 precursor). Due to its small size, the optimised TnpB gene editing system can be packaged into a single virus particle. It can still edit efficiently and recognise alternative gene sequences. In collaboration with the team of Michael Krauthammer, also a professor at UZH, they developed a new AI model that is able to predict the efficiency of TnpB editing at any target site. This makes reliable experimental design in terms of genome editing easier and faster.

Fighting cholesterol

The new UZH method is primarily a breakthrough for gene therapies in humans. For example, new gene therapies have recently been approved for the hereditary disease haemophilia. The UZH researchers immediately set about investigating whether the optimised gene scissors could be used to modify a gene that lowers cholesterol levels.

At the heart of the new UZH gene scissors is, of course, red biotechnology. But genome editing is also set to revolutionise agriculture. Long-desired plant traits seem to be within reach.

Examples of the application of genome-edited plants from breeding research could also be of interest to Swiss agriculture. In addition, it is not just about applications: new genome editing methods are constantly being developed for plants using CRISPR-Cas variants. Syngenta scientists, for example, have further developed the CRISPR-Cas12a gene scissors to significantly optimise it as a tool for improving plants.

Innovation abroad

In green biotechnology, however, these innovations are increasingly taking place outside Switzerland and Europe. The major agricultural markets such as the USA, Brazil and China are leading the way. In the USA and Brazil, genome-edited seeds are not considered to be genetically modified and are therefore not subject to strict regulation. It is no wonder that companies are increasingly concentrating their research in these countries. Genome-edited leafy vegetables from the agricultural technology start-up Pairwise are already available on the North American market. Bayer has signed a licence agreement with the company. The variety is a cross between colourful leafy vegetables with a higher nutritional value than lettuce and a unique, fresh taste that has been achieved using genome editing. In China, a genome-edited wheat was approved for cultivation in May 2024. The wheat is more resistant to disease and promises higher yields. Overall, China is leading the way in the development of genome-edited plants: 509 of the 900 known breeding projects worldwide at the end of May 2024 come from China, according to the Point newsletter from scienceindustries. ‘The main breeding goals include increased yields, disease resistance, stress tolerance and improved food and feed quality.’

Patent pending

One thing is clear: innovation will not wait for the doubters in Europe and Switzerland – this applies to the use of genome editing in both humans and plants. Of course, the UZH researchers immediately applied for a patent for their groundbreaking invention, as they write in their publication. In doing so, they have laid the foundation for ensuring that this does not remain an academic gimmick. Possible commercial applications are obvious: in mice treated with the new TnpB gene scissors, cholesterol levels were reduced by almost 80 per cent. With this promising result and the patent, the invention is also of interest to investors.