Zheludev, Ivan N.Edgar, Robert C.Lopez-Galiano, Maria JoseLa Peña Del Rivero, Marcos DeBabaian, ArtemBhatt, Ami S.Fire, Andrew Z.2024-12-262024-12-262024-11-140092-8674https://riunet.upv.es/handle/10251/213268[EN] Here, we describe "obelisks,"a class of heritable RNA elements sharing several properties: (1) apparently circular RNA 1 kb genome assemblies, (2) predicted rod-like genome-wide secondary structures, and (3) open reading frames encoding a novel "Oblin"protein superfamily. A subset of obelisks includes a variant hammerhead self-cleaving ribozyme. Obelisks form their own phylogenetic group without detectable similarity to known biological agents. Surveying globally, we identified 29,959 distinct obelisks (clustered at 90% sequence identity) from diverse ecological niches. Obelisks are prevalent in human microbiomes, with detection in 7% (29/440) and 50% (17/32) of queried stool and oral metatranscriptomes, respectively. We establish Streptococcus sanguinis as a cellular host of a specific obelisk and find that this obelisk's maintenance is not essential for bacterial growth. Our observations identify obelisks as a class of diverse RNAs of yet-to-be- determined impact that have colonized and gone unnoticed in human and global microbiomes.Reconocimiento - No comercial - Sin obra derivada (by-nc-nd)Human microbiomesRNAGenomeObelisksProteinArtículo10.1016/j.cell.2024.09.033Abierto39481381