Scientists have long known that unusual aquatic creatures known as tardigrades were capable of surviving boiling, freezing, and intense radiation, but a new study led by researchers at the University of Tokyo discovered exactly what makes these creatures so close to indestructible.
Writing in the journal Nature Communications, Professor Takekazu Kunieda and his colleagues explained that the creatures also known as water bears possess a protein that protects their DNA by swaddling it like a baby in a blanket — a survival secret that they believe could eventually be used to protect human cells from radiation, according to the Washington Post.
Tardigrades, explained BBC News, roll themselves up into little desiccated balls (meaning that they become severely dehydrated) in order to protect themselves from extreme conditions, such as sweltering heat, prolonged arid conditions or even the vacuum of space. Now, however, Prof. Kunieda’s team has pinpointed the genetic causes that prevent damage to the creature’s DNA.
While examining the tardigrade genome, they found a specific protein that attaches itself to the creature’s DNA and which appeared to have a protective mechanism. The protein, dubbed Dsup (short for damage suppressor) is believed to not only protect tardigrade DNA from the impact of radiation exposure and other harmful stimuli, but also repairs any damage that does occur.
“We guess that Dsup binds densely to DNA to provide a shield against environmental stress, somehow making DNA inaccessible to any damaging agents,” Prof. Kunieda explained to New Scientist. “To our knowledge, this is the first identification of a DNA-associating protein which confers DNA protection and improved tolerance to radioactivity in animal cells.”
Protein could protect cells during space travel and cancer treatments
After discovering Dsup, the researchers modified human cells in order to make them produce the protein. They found that the enhanced cell cultures experienced about 40% less damage from X-rays than unaltered cells, suggesting that Dsup could ultimately be used to help protect the DNA of men and women from radiation as well.
Furthermore, Kuneida told New Scientist that the protection all but disappeared when he and his colleagues disrupted the Dsup gene using RNA, clearly illustrating that it is the primary factor in delivering this cellular protection. While transferring the protein into other animals using genetic engineering could boost their resistance to radiation, he warns that this could be difficult.
Nonetheless, the Tokyo researcher is optimistic that it could be done: “As Dsup improved the radiation tolerance of human cultured cells, I hope it might be possible to improve the radiation tolerance of individual animals… It could be helpful for space flight, radiotherapy and radiation workers in the far future,” protecting them during cancer treatments or from cosmic rays.
University of Edinburgh Professor Mark Blaxter, who was not involved in the research, said that the findings were “groundbreaking,” telling BBC News that “this is the first time an individual protein from a tardigrade has been shown to be active in radiation protection… [And] radiation is one of the things that’s guaranteed to kill you.”
Image credit: S Tanaka/H. Sagara/T Kunieda