Biologists have made human cells in 1.5 times more resistant to radiation effect by adding one of the proteins of animals – the most hardy and tenacious creatures on Earth that can survive getting into open space.
In 2007, scientists made a surprising discovery when analyzing data collected by the Russian spacecraft Foton-M3: it turned out that cichodajki, small invertebrates, distant relatives of crabs and insects are able to survive for a very long time in open space and even multiply in conditions of complete weightlessness and the lack of food and water.
When scientists began to calculate and study the genes of animals, they expect a big surprise – more than 6.5 thousand of DNA from 38 thousand genes (18%) were borrowed from other organisms. Most of them were obtained from bacteria-the extremophiles, but in the genome of animals as there are genes of plants, fungi and archaea.
Takuma Hashimoto (Takuma Hashimoto) from the University of Tokyo (Japan) and his colleagues found one of the genes, which may explain the extremely high survivability of the animals. For this, they have decoded the genome of the resistant species of these animals, Ramazzottius varieornatus and also followed changes in the DNA of the animals when they are drying and recovery.
This analysis showed that the proportion of genes they have stolen is actually much lower than predicted by the biologists earlier – their share is 1.8%, not 18% and most of them were inherited from the fungi and not germs. In addition, the total number of genes in their genome has dropped from 38 to 19 thousand.
On the other hand, the genome of the animalcules, as it turned out, about half is composed of unique segments of DNA, which is unique in the genomes of any other creature on Earth. Studying these genes, Hashimoto and his colleagues ran into protein Dsup, which is an unusual way associated with DNA.
He, as suggested by scientists that it plays a key role in the protection of animals from radiation, giving broken strands of DNA to be lost and a wrong way to reconnect to the arrival of emergency cell help in the form of proteins, putting breaks in the DNA strands.
Following this idea, biologists have transplanted a gene into the genome Dsup normal E. coli, causing her to produce this protein in large quantities. The team then Hashimoto transferred this gene and protein in cultures of human cells in vitro and irradiated them with ultra-high radiation dose.
As shown by this experiment, the number of single and double breaks in the DNA of cells fell by 40% after such treatment, which suggests that the protein Dsup really protects the animals from radiation and helps them to survive in space. Cell cultures that are protected by the protein, continued to increase even after irradiation, whereas almost all the cells in the control tubes stopped growing and died.
Another secret to the survival of animals in space and other extreme conditions may be that they do not have the number of chains of genes associated with stress response and turn on the suicide program in the cells during a critical shortage of water, nutrients, or other severe conditions. Further study of the DNA of these animals, as scientists hope, will help us to understand how to protect travelers to Mars and other planets from the action of large doses of radiation and how to teach the human body to survive in the harsh environment of space.