Molecular study of newly discovered tardigrade species helps explain ability to withstand high doses of radiation

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A team of biologists affiliated with several institutions in China has learned more about the means by which tardigrades are able to withstand high doses of radiation. In their study, published in the journal Science, the group focused on a newly found species of the creature.

Tardigrades are famous for their ability to survive in environments that other creatures cannot—they survive on the outside surface of the International Space Station, for example. In this new effort, the research team wanted to learn more about these remarkable abilities.

The work began six years ago, after the researchers discovered a new species of tardigrade in Henan Province. They named it Hypsibius henanensis and sequenced its genome. They found it had 14,701 genes, of which approximately 30% were unique to tardigrades. They then turned their attention to the effects of bombarding the creature's DNA with gamma rays—from low to very high doses.

The researchers discovered that 2,801 of the genes in the tardigrade's DNA were involved in DNA repair. More specifically, they found three key factors that helped it survive exposure to radiation.

The first was its ability to repair its DNA once damaged. DNA is damaged by radiation, such as gamma rays, as they knock electrons loose from their constituent atoms, ionizing them. Ionization can lead to helix breakage and sometimes the development of cancerous tumors. H. henanensis, the researchers found, is able to quickly repair such damage using a protein made only by tardigrades called TRID1.

The second factor involved a gene that was switched on during exposure to radiation, resulting in the generation of two proteins that are known to be important for mitochondrial synthesis of ATP—in tardigrades, it appears they also help with DNA repair.

The third factor was H. henanensis's ability to minimize damage from radiation by producing a large number of proteins that serve as effective antioxidants—they clear out free radicals before they can cause problems in the creature's cells.

More information: Lei Li et al, Multi-omics landscape and molecular basis of radiation tolerance in a tardigrade, Science (2024). DOI: 10.1126/science.adl0799

Journal information: Science

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