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. 2024 Nov 14;187(23):6521-6536.e18.
doi: 10.1016/j.cell.2024.09.033. Epub 2024 Oct 30.

Viroid-like colonists of human microbiomes

Ivan N Zheludev  1 , Robert C Edgar  2 , Maria Jose Lopez-Galiano  3 , Marcos de la Peña  3 , Artem Babaian  4 , Ami S Bhatt  5 , Andrew Z Fire  6
Affiliations

Viroid-like colonists of human microbiomes

Ivan N Zheludev et al. Cell. .

Abstract

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.

Keywords: RNA metaviromics; hepatitis delta virus; human microbiome; viroid.

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Conflict of interest statement

Declaration of interests The authors declare no competing interests.

Update of

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