CRISPR–Cas9 Technology
The CRISPR–Cas9 system is one of the most exciting developments in molecular biology in the last ten years, massively increasing scientists’ ability to tinker with cells. It is a scalpel technology for gene manipulation, precise and able to be specifically controlled without off target effects. It is also cheap, quick and easy to use, and as a result has swept through labs around the world.
The system has already been used for a wide range of applications, such as creating mosquitoes that are resistant to carrying malaria, treating muscular dystrophy, encode a film in the genomes of living bacteria, altering the wool colour of sheep, making super muscled goats and dogs, and engineering mini-pigs.
The CRISPR–Cas9 system is derived from a naturally occurring mechanism developed by bacteria over millions of years to defend themselves from viral infections. There are two main components of the CRISPR–Cas9 system, an enzyme (Cas9) that acts like a pair of scissors to cut DNA, and a small RNA molecule (CRISPR) that directs the scissors to a specific location to make the cut. Generally, the cell’s native DNA repair machinery then repairs the cut.
However, this repair machinery often makes mistakes. Scientists can therefore use this system to precisely interrupt a gene and work out what it does. For example, if the repair machinery makes an error, this may completely disrupt the ability of the cut gene to function. As the gene no longer functions in its purpose, scientists can then see what effect this has on the cell.
There are other advantageous aspects to the system. Scientists can use a different DNA repair mechanism to repair the cut as they wish, for example by using a template to edit the genome and inserting additional DNA sequences. As the cut can be made anywhere in the genome, and the template can code for any gene, scientists can essentially edit the genome with nearly any sequence they desire at nearly any location of their choosing.
A variant CRISPR–Cas9 system can also be used to controllably switch a gene on and off, without affecting the sequence of the gene. For example, switches based on light, chemicals etc have been developed for control of gene expression.
A further variant CRISPR–Cas9 system has been developed that can control epigenomic marking of DNA. The epigenome is a series of markers on DNA that are a record of the chemical changes to the DNA of an organism. Unlike the underlying genome, which is largely static within an individual, the epigenome can be dynamically altered by environmental conditions. Furthermore, these changes can be passed down to an organism’s offspring. The epigenome can govern access to DNA, opening it up or closing it off to the proteins needed for gene expression.
The markers change over time, added and removed as an organism develops and its environment shifts. The location and activity of these markers can be manipulated using a CRISPR–Cas9 system.
The holder of key patents could make hundreds of millions of dollars from CRISPR–Cas9’s applications in industry. The technique has already sped up genetic research; and researchers are using it to develop treatments for human diseases and disease-resistant livestock and crops.
The Patent Stoush
In 2012, Jennifer Doudna at the University of California-Berkeley, Emmanuelle Charpentier, then at the University of Vienna, and their colleagues outlined how the CRISPR–Cas9 system could be used to precisely cut isolated DNA. Berkeley filed patent applications in May 2012, their patent applications exclusively discussed the use of the system in prokaryotic bacterial cells but had claims to use of the CRISPR system without regard to the type of cells it was used in.
In 2013, Feng Zhang and his colleagues at the Broad Institute of MIT and Harvard – and other teams – showed how the CRISPR–Cas9 system could be adapted to edit DNA in eukaryotic cells such as plants, livestock and humans. The Broad team filed the first of their patent applications in December 2012 at the time of filing they requested that the United States Patent and Trademark Office (USPTO) ‘fast-track’ its patent examination process for their applications.
In the US
Although Berkeley filed for patents earlier, the USPTO granted the Broad’s patents first, due to the fast tracked examination process.
Berkeley then filed an ‘interference’ proceeding, in an effort to have the Broad’s patents revoked. An interference is a legal proceeding to determine who was the first to invent a given technology. The case was presented on the basis that the Broad’s patents overlapped with Berkeley’s first filed and still pending CRISPR patent applications.
However, in February 2017 the USPTO patent judges determined that there was no interference, meaning that the Broad’s invention is distinct from Berkeley’s, and the Broad patents will stand.
This decision was appealed by Berkeley in April 2017. If the appeal is unsuccessful, Broad will keep its CRISPR patents, while Berkeley’s patent application – which includes claims encompassing CRISPR without regard to cellular environment – should issue as a patent. In this case, researchers wishing to use the CRISPR technology will need a license from both parties (Berkeley for CRISPR– Cas9 in any cell and especially prokaryotic cells, Broad for CRISPR– Cas9 in eukaryotic cells).
If the appeal is successful, the case will be returned to the USPTO for further proceedings in relation to the alleged interference, which could lead either to the same outcome, or to a decision to remove the Broad claims to using CRISPR in eukaryotic cells.
Further afield
Patent applications all over the world for both parties are still being prosecuted. Although the USPTO found that the Broad patent was inventive in light of the Berkeley patent on the grounds that the Berkeley patent did not suggest a eukaryotic use and that additional invention beyond that described in the Berkeley patent application was required, other Patent Offices such as the European Patent Office could come to another conclusion and find that the Berkeley patent provided ‘sufficient motivation’ to try the technique in eukaryotic cells, thus rendering the Broad applications lacking in an inventive step. Berkeley has been granted patents in the UK and Europe.
Other players
In addition, there are other groups battling it out for patents to various certain aspects of the CRISPR–Cas9 gene editing system and related systems that use a component other than Cas9. Over time, holders of those patents may try to assert those rights.
The outcome
Whatever happens in each Patent Office, this story will continue for some time. The battle is not between two universities, but between commercial investors in technology that could be worth hundreds of millions of dollars, and has already attracted invested funds and a market cap of over a billion dollars.
Read more from other Wrays thought leaders in volume 4 of The Gatherer.
