Two years ago, Prof. Emmanuelle Charpentier of Germany’s Max Planck Unit for the Science of Pathogens and University of California biochemist Prof. Jennifer Doudna – received the Nobel Prize in Chemistry for their pioneering work in CRISPR gene editing.
CRISPR systems are the immune systems of bacteria from viruses. Bacteria use the CRISPR-Cas systems – enzymes from bacteria that control microbial immunity – as a kind of molecular “search engine” to locate viral sequences and split them to disable viruses. Two scientists who studied this sophisticated defense mechanism,
Israeli astronaut Eytan Stibbe, as part of the Rakia mission launched into space in April under the leadership of the Ramon Foundation and the Israel Space Agency, conducted Tel Aviv University (TAU) research in the International Space Station to test genetic diagnosis under microgravity conditions using the CRISPR system. The researchers proved that CRISPR-Cas can be utilized to precisely and reliably identify viruses and bacteria that infect crew members during space missions.
The study was led by Dr. Dudu Burstein – a former member of Doudna’s lab who spent several years as a postdoctoral associate learning about CRISPR-Cas and went on to work at TAU’s Shmunis School of Biomedicine and Cancer Research, together with Dr. Gur Pines from the Volcani Center for Agricultural Research near Tel Aviv.
The CRISPR system has recently been used to identify various organisms with extreme precision, based on recognition of specific DNA sequences. As part of their scientific vision, the Israeli researchers hypothesized that genetic diagnostics using this method, which requires minimal and easily operated equipment, could be suitable for long space missions on the space station or on future missions to explore the moon and Mars.
“Conditions in space are extremely problematic, and treatment methods are limited, so it is essential to identify pathogens in a rapid, reliable, and straightforward method,” said Burstein. “Tests like PCR, which we are now all familiar with, require trained personnel and relatively complex equipment. In the International Space Station, we tested a CRISPR-based detection method developed by Dr. Janice Chen and colleagues in the Doudna lab.”
First, the DNA is amplified – each targeted DNA molecule is duplicated many times, and then the CRISPR-Cas goes into action. If it identifies the target DNA, it activates a fluorescent molecular marker. The fluorescence makes it possible to know whether the bacteria or viruses of interest are indeed present in the sample. “This whole process can be conducted in one tiny test tube, so it can suit well the astronauts’ needs,” he continued.
Doctoral student Dan Alon and Dr. Karin Mittelman planned the experiment in detail and conducted it countless times in the lab under various conditions. After reaching the desired result, they prepared a kit, including the CRISPR-Cas system and the other components required for detection. Eventually, this kit was launched together with Eytan Stibbe to the space station.
The results of the experiments conducted by Stibbe were very successful, enabling the researchers to prove that it is indeed possible to perform precise and sensitive CRISPR-based diagnosis even in an environment with virtually no gravity. “This is the first step towards the simple and rapid diagnosis of diseases and pathogens even on space missions,” concluded Burstein. “There is still work to do on the next stages – simple extraction of DNA from samples, making the system more efficient – so that it will be able to test a variety of organisms in one test tube and diagnosing more-complex samples. It was inspiring to see our test kit in Eytan’s hands in the space station, and we’re even more excited by the possibility that such kits will help future astronauts on their extraterrestrial missions.”