Credit: Julia Yellow
Gene editing has burst into the spotlight courtesy of quick and easy CRISPR technology, and scientists have now found another way of editing genes that could be even better.
Currently one of the hottest names in biotech, CRISPR-Cas9 is the name for the viral defence system researchers discovered in bacteria. CRISPR stands for a guiding sequence of RNA which locks onto a specific DNA strand, and Cas9 is the ‘cutting’ enzyme that snips the strand out. When Cas9 and its guiding CRISPR strand are coupled, they’re an excellent gene editing tool. They’re accurate, relatively cheap and easy to make.
But CRISPR isn’t perfect
It’s the most effective overall tool, but there are some issues with accuracy. It is extremely specific, but when you’re dealing with 3 billion base pairs, extremely isn’t always enough. It’s relatively recent and needs some streamlining before it’s ready for human usage. The CRISPR-Cas9 system itself is also currently in a patent war, which could stifle progress.
The older Cas9 enzyme cuts DNA bluntly (below), but Cpf1 leaves ‘sticky’, overhangs (above). This makes mutations harder, and inserting new sequences easier.
One of the teams involved with the patent dispute has now stumbled across another similar snipping enzyme, called Cpf1. The Cpf1 enzyme is smaller
which makes it easier to get inside cells. While Cas9 cuts in a blunt way which makes mutations more frequent when the cut rejoins itself, Cpf1 cuts and leaves overhangs.
Not only does Cpf1 potentially improve on accuracy and ease of application, but it could also avoid the tricky legal battles of Cas9. Currently no other team claims ownership. While Cas9 may be less efficient in some ways, the two tools are actually complementary, as both proteins target different parts of the genome differently.
There could be more out there
This new enzyme was discovered by scanning a database of bacterial gene sequences. Bacteria are constantly evolving new ways to tackle viruses, so it’s likely there are many more similar systems out there. Multiple different enzymes could make patenting hard, and make gene editing even more accessible.
Gene editing is still in its early days, but it’s living up to the hype so far. Like any radical technology it requires appropriate caution, but things are getting very exciting.
Read more at The Economist