Taylor Opolka (University of Notre Dame)

Abstract:

Published in Cell in November of 2024, “Viroid-like colonists of human microbiomes” - reported by the Fire lab of Stanford University’s School of Medicine - chronicles the discovery of a never-before-seen class of heritable, rod-like RNA elements dubbed “RNA Obelisks.”1 These elements closely resemble viroids - infectious RNA entities that are smaller than viruses and lack protein-coding capabilities - in that they have small, circular genomes, but are set apart by the presence of open reading frames that encode a family of novel “Oblin” proteins. Analysis of metatranscriptomic databases reveal that Obelisks may be abundant globally across ecological niches, even among members of human microbiomes. With thousands of distinct Obelisks identified and no detectable similarities to other known biological agents, it is clear that these novel entities form their own diverse phylogenetic group is hitherto unknown. This work highlights the gap in traditional methods used to discover and characterize heritable RNA elements, opening the door for exciting new inquiries and challenging our understanding of the limits of the genome and biological information transfer.

References

[1] Zheludev, Ivan N. et al. Viroid-like colonists of human microbiomes. Cell 2024 187, 23, 6521 - 6536.e18