Science & Technology

We Finally Know How Tardigrades Survive Deadly Radiation

They're cute. They're squishy. They're resilient. Whether you call them water bears or moss piglets, you probably know two things about the microscopic animals scientists call tardigrades: they're adorable and they can survive anything.

Freezing cold? No problem. Deadly chemicals? No problem. Extreme radiation? No problem. These guys are tough. They've even posted up on the moon.

But how?

Scientists have known for a long time that tardigrades can survive in extreme environments, but they're just beginning to figure out how they do it. In a paper published in the journal eLife in October 2019, researchers at the University of California, San Diego, bring new clarity to the mystery of tardigrade resilience with a discovery that could have huge implications for the future of biotechnology.

Compact for Storage but Vulnerable to the Elements

Cells manage to store an incredibly long set of instructions in an incredibly small space. To manage all that information, they wrap strands of DNA, which are made up of base pairs connected in a long, twisting double helix, around special proteins to make a stringy, information-rich material called chromatin. Cells form chromosomes by folding and wrapping the chromatin over and around itself.

Chromatin is a great way to store and use the code of life, but one drawback is that it leaves its chemically encoded information vulnerable to the environment. Unless you happen to be a water bear.

Radiation can react with water in the cells of living things to make dangerous molecules called hydroxyl radicals. Hydroxyl radicals want to react with — that is, change — the first molecule they come across. If a hydroxyl radical interacts with the DNA in chromatin, it can corrupt the genetic message and indirectly cause certain types of cancer. This kind of DNA damage threatens creatures across the tree of life, but tardigrades have found a way to protect their chromatin from radiation damage: a protein called Dsup.

Thumbs Up for Dsup

It turns out that Dsup, which stands for Damage suppression protein, doesn't bother with the radiation itself. Instead, Dsup protects the tiny animals' genomes by binding to the chromatin and creating a protective shield that stops hydroxyl radicals from ever making contact with the DNA.

"We see that [Dsup] has two parts, one piece that binds to chromatin and the rest of it forming a kind of cloud that protects the DNA from hydroxyl radicals," said James T. Kadonaga, a distinguished professor at UC San Diego and the Amylin Endowed Chair in Lifesciences Education and Research, in a press release.

Did tardigrades develop Dsup in evolutionary preparation for a microscopic lunar mission? Definitely not. Some tardigrade ancestors probably first developed a version of Dsup by random chance. The mutation stuck around because the protein protected the tiny animals from DNA damage during dry periods when they went into a dormant state of dehydration, Kadonaga said. That dehydrated state can lead to the same kind of damage caused by hydroxyl radicals.

Now that we better understand how Dsup works, we may be able to use the protein as source material or inspiration for new biotechnologies that protect other kinds of cells from certain types of radiation damage. The researchers hope their findings will improve cell-based therapies and diagnostic tests that rely on cells living in culture.

Get stories like this one in your inbox or your headphones: Sign up for our daily email and subscribe to the Curiosity Daily podcast.

Want to find tardigrades in your own backyard? It's possible! Check out "How To Find Tardigrades and Observe Them Through a Microscope" by Michael W. Shaw and get to hunting. Purchasing through that link supports Curiosity.

Written by Grant Currin October 28, 2019

Curiosity uses cookies to improve site performance, for analytics and for advertising. By continuing to use our site, you accept our use of cookies, our Privacy Policy and Terms of Use.