Viperin and Argonaute: Crucial Immune System Proteins Traced Back to Ancient Microbes Asgardarchaeota

Researchers from the University of Texas at Austin, in a study published in Nature Communications in July 2024, revealed that the viperin and argonaute proteins, which play a crucial role in the immune system against viral infections in eukaryotic organisms, including humans, actually originated from ancient microbes known as Asgard archaea or Asgardarchaeota. This discovery came after the researchers explored the diversity and distribution of 2610 complete defence systems within Asgardarchaeota, which include 89 unique systems such as argonaute, NLR, Mokosh, viperin, Lassamu, and CBASS. Through phylogenetic analysis, the researchers confirmed that eukaryotic argonaute and viperin proteins are derived from Asgardarchaeota. The study also demonstrated that viperin from Asgardarchaeota exhibits anti-phage activity when expressed in bacterial cells. Additionally, Asgardarchaeota argonaute proteins were found to have argonaute-PIWI domains, crucial components in eukaryotic RNA interference systems. These findings clarify that the contribution of Asgardarchaeota to the early evolution of eukaryotic cells extends beyond cell structure to include the immune systems that protect against infections.

Source: https://doi.org/10.1038/s41467-024-50195-2