New gene-editing system uses ‘jumping genes’ to insert DNA without cutting them

Gene-editing technology has proved to be a really powerful one, with ability to revolutionize the way diseases are treated. Researchers have now gone a step ahead by creating a new gene-editing system that can insert DNAs without cutting or pasting them, with the help of ‘jumping genes’.

A team of scientists from MIT and Harvard have created a new CRISPR-based system that has the ability to insert new DNA sequences without needing to make cuts – making the process safer and more accurate.

Normally, CRISPR tools are based on a bacterial self-defense system where it uses enzymes like Cas9 to snip a piece of the virus’ DNA it encounters and stores it within themselves. This lets the bacteria easily identify and fight the virus if it ever occurs again, explained New Atlas.

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For the new kind of system, the team, instead of using the defensive enzymes like Cas9, they investigated DNA sequences named transposons, also dubbed as ‘jumping genes’ due to their tendency to jump around in the genome, with subtypes guided by proteins called transposases.

The team isolated the enzyme Cas12k from two species of cyanobacteria and manipulated them into jumping to specified targets in the genome. They then inserted the new DNA sequences without the need to cut anything. The team called the new system as CRISPR-associated transposase (CAST).

“We dove deeply into this system in cyanobacteria, began taking CAST apart to understand all of its components, and discovered this novel biological function,” explained first author Jonathan Strecker.

“CRISPR-based tools are often DNA-cutting tools, and they’re very efficient at disrupting genes. In contrast, CAST is naturally set up to integrate genes. To our knowledge, it’s the first system of this kind that has been characterized and manipulated,” he continued.

During tests, the team was able to insert new DNA sequences up to 10 base pairs long into exact locations on the genome. The system worked successfully 80% of the time, but the team still needs to further improve it.

Moreover, this new CAST technique could be used in many applications such as healing genetic diseases by disabling the harmful mutation and inserting a new, healthy version instead. Also, it could be used to add new, useful sequences without snipping off any existing gene, and hence inserting a new ability.

“For any situation where people want to insert DNA, CAST could be a much more attractive approach,” as per senior author Feng Zhang. “This just underscores how diverse nature can be and how many unexpected features we have yet to find.”