|NASA astronaut Christina Koch works on the “Genes in Space-6” investigation [Credits – NASA]|
In a part of Genes in Space-6 experiment, which is about studying DNA breaks to protect future space travelers, the researchers reported this first completion of the entire process in space in a published paper. The researchers directed the method of repair, and sequenced the patched-up DNA to determine whether its original order was restored.
These results significantly expand the space station’s molecular biology toolkit, enabling studies of DNA repair and a variety of other biological investigations in microgravity.
|From left to right: Michelle Sung, Rebecca Li, Aarthi Vijayakumar and David Li
[Credits: GENES IN SPACE]
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 evaluate the entire damage and repair process in space.
Astronauts may be at risk for harmful DNA damage caused by ionizing radiation. Double-strand breaks are a type of DNA damage that can be repaired by two major cellular pathways: non-homologous end joining, during which insertions or deletions may be added at the break site, and homologous recombination, in which the DNA sequence often remains unchanged. Previous work suggests that space conditions may impact the choice of DNA repair pathway, potentially compounding the risks of increased radiation exposure during space travel.
However, understanding of this problem has been limited by technical and safety concerns, which have prevented integral study of the DNA repair process in space.
The CRISPR/Cas9 gene editing system offers a model for the safe and targeted generation of double-strand breaks in eukaryotes. In the research paper, its describes that a CRISPR-based assay for DNA break induction and assessment of double-strand break repair pathway choice entirely in space.
Genes in Space and other DNA-related research on the space station also has produced advances in the hardware needed. Tools on Earth do not necessarily lend themselves to spaceflight, says Sarah Rommel, the paper’s primary author and a researcher in the Microbiology Laboratory at Johnson.
“We cannot take exactly what we have on Earth and simply put it in space, because we have to keep the crew and all the environmental life systems on board safe. For example, we made our own custom kits for the whole process, looking at how to use the least amount of the safest materials and still get the best science,” says Sarah.