Sturdy little buggers
Tardigrades are amazing creatures famous for their extreme survival skills. Their collection of abilities make up for their small stature. They are capable of surviving under the harshest conditions including the vacuum of outer space, extreme temperatures, great pressure (equivalent to six times as much pressure under the ocean), dehydration, and being frozen solid for years.
If tardigrades were Pokémon, they would be on the legendary side.
To top it off, tardigrades can survive radiation levels that are very lethal to most organisms. Now, scientists have finally unlocked what makes this all possible.
It's all in the proteins
According to a study published in Nature Communications, a group of researchers found the anti-radiation ability of tardigrades was due to a special protein they have taken to calling "Dsup," which is short for "Damage suppression." Dsup was discovered by Takekazu Kunieda and his team at the University of Tokyo, after sequencing the complete genome of a tardigrade species called Ramazzottius varieornatus.
Dsup proteins embrace tardigrade DNA and envelope it, protecting it from harm due to radiation, while keeping all of its normal functions intact. It is also capable of cleaning out DNA-damaging agents known as reactive oxygen species.
The best part is, Dsup can develop in other organisms, too, like human beings.
Kunieda tested this with lab-cultured kidney cells, genetically engineering these cells to produce Dsup themselves. "The human cells that made Dsup saw a reduction of around 40 to 50 percent in the DNA damage caused by X-rays compared with control cells,” Kunieda noted. When RNA was used to sabotage the Dsup gene, the protection against radiation disappeared completely. This proved that Dsup is the key factor.
Assuming this ability can be successfully recreated in all the cells of a fully-grown organism like us, it could make human beings and other animals immune to radiation. "It could be helpful for space flight, radiotherapy and radiation workers in the far future,” Kunieda believes. That's a big if, of course.
In any case, Kunieda's research also laid to rest a theory that tardigrade DNA was largely scavenged from other bacterial organisms with a process called horizontal gene transfer. As it turns out, most of the tardigrade DNA is "home-grown", confirming a study from earlier this year.