The US National Aeronautics and Space Administration (NASA) agency said on 23 May that astronauts aboard the International Space Station (ISS) had successfully edited DNA using CRISPR/Cas9 technology in space for the first time.
The gene-editing tool was used as part of Genes in Space 6, an experiment exploring how space radiation damages DNA and how cells repair that damage in microgravity. Their findings could help scientists develop techniques to protect long-term space travelers from radiation.
In the six months that astronauts typically spend at the ISS, they are subjected to 30 times the radiation a human would typically receive in a year on Earth. Exposure to radiation can increase the risk of developing cancer, degenerative diseases and central nervous system problems.
According to NASA, an organism carries all of its genetic information in its deoxyribonucleic acid or DNA. This blueprint for life takes the form of specific sequences of nitrogen bases: adenine, cytosine, guanine, and thymine, represented by the letters A, C, G and T.
One type of DNA damage is double strand breaks, which are basically a cut across both strands of DNA. Cells repair these breaks almost immediately but can make errors, inserting or deleting DNA bases and creating mutations that may cause diseases such as cancer.
Genes in Space 6 looks at the specific mechanism that cells use to repair double strand breaks in space. The investigation takes yeast cells to the space station, where astronauts cause a specific type of damage to its DNA using a genome editing tool known as CRISPR-Cas9.
The astronauts allow the cells to repair the damage, then make many copies of the repaired section using a process called polymerase chain reaction (PCR) with an onboard device, the miniPCR. Another device, MinION, is then used to sequence the repaired section of DNA in those copies.
Sequencing shows the exact order of the bases to reveal whether the repair restored the DNA to its original order or made errors. The investigation represents a number of firsts, including the first use of CRISPR-Cas9 genetic editing on the space station and the first time scientists have been able to evaluate the entire damage and repair process in space.
It is part of the wider Genes in Space program, which was founded by miniPCR and Boeing. The program challenges students to come up with DNA experiments in space that involve using the PCR technique and the miniPCR device on the station.
Students submit ideas online and the program chooses five finalists, who are paired with a mentor scientist who helps them turn their idea into a presentation for the ISS Research and Development Conference. A panel of judges selects one proposed experiment to fly to the space station.
More than 550 student teams submitted ideas last year. The Genes in Space 6 investigation student team includes students from Mounds View High School in Arden Hills, Minnesota, and David Li, now a freshman at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts. Their mentor is Kutay Deniz Atabay at MIT.
Other investigators include members of NASA’s Johnson Space Center Microbiology group in Houston; G. Guy Bushkin, from the Whitehead Institute for Biomedical Research, in Cambridge; Melissa L. Boyer, Teresa K. Tan, Kevin D. Foley, and D. Scott Copeland at Boeing; and Ezequiel Alvarez Saavedra, Gleason, and Sebastian Kraves at Cambridge-based Amplyus, the parent company of miniPCR Bio.
“The damage actually happens on the space station and the analysis also happens in space,” Emily Gleason, one of the investigators from miniPCR Bio, said in a statement. “We want to understand if DNA repair methods are different in space than on Earth.”
“One thing the investigation will tell us is yes, we can do these things in space. We expect to see the yeast use the error-free method of repair more frequently, which is what we see on Earth; but we don’t know for sure whether it will be the same or not.” she added. “Ultimately, we can use this knowledge to help protect astronauts from DNA damage caused by cosmic radiation on long voyages and to enable genome editing in space.”