Tardigrades, or water bears, are everywhere. They lurk in your gardens and neighbourhood parks. They live on top of mountains and in deep ocean trenches, in hot springs and underneath ice. All they need is a little moisture.
They are the world’s great survivors. They can survive living in space, high levels of radiation, extreme temperatures (from -273 °C to almost 100 °C), pressures up to 7.5GPa, or no pressure–they can live in a vacuum.
The question, of course, is why can they survive when other species, particularly humans are so fragile and susceptible to damage. They can slow their metabolism and enter into a dormant state. They can revive after being frozen or losing up to 99% of their moisture. If we could learn how they do it, we may find the secret to making cryonics work.
Tardigrades have DNA, just like all living creatures on Earth. But their DNA, can resist the damage caused by radiation or severe dehydration. We now know this is partly thanks to the Dsup protein.
Last year, Japanese scientists published a paper in Nature Communications outlining their search for the genes behind the tardigrades superpowers. The scientists analysed gene expression from one species of tardigrades, Ramazzottius varieornatus, that is known to be particularly resistant to physiologically stressful situations.
They found that they tardigrade-specific DNA-associated protein, which they called Dsup. When they imaged the tardigrade cells to find out where Dsup protein was located, they almost always found it in the nucleus of the cell, right next to the tardigrade’s DNA. gene Dsup gene protects tardigrade DNA from X-ray radiation. When they inserted this gene into cultured human kidney cells (HEK293 cells), the modified cells were also more resistant to the DNA-damage caused by X-ray radiation or by hydrogen peroxide.
With the recent experiments showing that the CRISPR gene-editing tools might be safe to use in human cells and human embryos, maybe one day we will choose to steal the Dsup gene from tardigrades to make our DNA less susceptible to stress-induced breaks.
You can find my tardigrade-inspired short story here.
The Scientific Paper (free and open access!):