Scientists are tinkering with tardigrades’ DNA to figure out how they get their superpowers

As we learn more about how tardigrades survive in extreme conditions, this knowledge can be applied to biomedical technologies, such as preserving and transporting human organs.

Tardigrades are almost indestructible. You can expose them to intense heat, freeze them, vacuum them, or even dry them completely: it doesn’t seem to affect them much. These exceptional properties make tardigrades a fascinating subject for researchers, interested in uncovering their secrets not only out of curiosity, but also because of possible applications. And in New study The researchers focused on the core of their strange characteristics: the genome.

Genome
So we know that some species of tardigrades have extreme and unusual resistance to conditions that would be fatal to most other life forms. However, the genetic basis of this special ability remains a mystery. “To understand the superpowers of tardigrades, we first need to understand how their genes work,” explains researcher Takekazu Kunieda. “My team and I have developed a way to edit, add, delete or replace genes, as you would with computer data, in hardy tardigrade species. Ramazotius variornatus. This now allows us to study the genetic characteristics of tardigrades, similar to the way we do with laboratory animals such as fruit flies or roundworms.

CRISPR
The team applied a recently developed technique called CRISPR direct parentage (DIPA-CRISPR), based on the well-known CRISPR gene editing technology (see box). This method acts as a genetic scalpel to cut and modify specific genes more precisely than ever before. DIPA-CRISPR has the ability to influence the genome of the target organism’s offspring, and has previously worked effectively in insects. Now researchers have applied this technique to another organism for the first time. And with success. Ramazotius variornatusa female species that reproduces asexually, constantly producing offspring with two identical copies of the same modified genes, making this species ideal for DIPA-CRISPR.

What is CRISPR again?

CRISPR stands for clustered regularly interspaced short palindromic repeats, and is part of a particularly effective defense mechanism that bacteria use to combat small virus particles (also called phages). These virus particles can literally destroy bacteria. They do it like this: they latch on to the bacterial cell and pump out its DNA, and then use the bacteria to copy themselves thousands of times. Once this succeeds, the virus particles explode the bacteria and thousands of copies begin searching for other bacteria with which they can repeat the trick again. Fortunately for bacteria, they are not defenseless in this entire scenario; It has a defense mechanism called CRISPR-Cas, which consists of two parts. One part looks for enemy DNA and the other cuts that DNA. Years ago, researchers came to the fascinating conclusion that this bacterial defense mechanism could also be used to turn off certain genes in living cells. Or to detect “wrong” sections of DNA, cut them out and replace them with an alternative piece of DNA. In short: CRISPR systems provide us with an easy, fast and highly accurate way to edit DNA. And not just DNA from viruses, but also in plants, animals and humans. It is expected that CRISPR technology will be used in the future to combat genetic diseases, as well as retroviruses found in DNA, such as HIV.

In short, using CRISPR, researchers have now been able to manipulate tardigrade DNA. This immediately led to the production of genetically modified offspring. “We just had to inject CRISPR-programmed tools, which targeted specific genes for deletion, into a parent’s body to produce modified offspring,” explains researcher Koyuki Kondo. “We have also been able to obtain transgenic offspring by adding additional DNA fragments by injection. This allows us to precisely edit the genomes of tardigrades. In this way we can, for example, determine how individual genes are expressed or what their specific functions are.” performed by these genes.

superpower
By editing specific tardigrade genes, researchers can study which of these genes are responsible for the tardigrade’s flexibility and exactly how this flexibility works. The most prominent “superpower” of Ramazotius variornatus, is that this species can survive severe drought for long periods of time. This may be due in part to the presence of a specific gelatinous protein in their cells. This has interesting implications. For example, Kunieda and other tardigrade researchers believe it is worth studying whether an entire human organ can be successfully dehydrated and rehydrated without leading to deterioration. If this proves possible, it could have a revolutionary impact on the way organs are donated, transported and used during life-saving surgeries.

Overall, researchers have succeeded in modifying the tardigrade genome. This represents a major advance in our understanding of the genetic basis of their remarkable ability to survive. At the same time, this may seem like “science fiction” and manipulation to some. “I understand that some people are concerned about gene editing,” Kunieda says. “But we conducted gene editing experiments under strictly controlled conditions and stored the GMOs safely in a sealed chamber. CRISPR can be an extremely powerful tool to better understand life and support practical applications that can make a positive difference in the world. Tardigrades do not provide Not only an insight into potential medical breakthroughs, but their fascinating properties also tell a fascinating evolutionary story. We hope to explore this story further by comparing their genomes to those of closely related organisms using the new DIPA-CRISPR technology.