Mining Metatranscriptomes Reveals a Vast World of Viroid-like Circular RNAs

Overview

Journal Cell

Publisher Cell Press

Specialty Cell Biology

Date 2023 Jan 25

PMID 36696902

Authors

Benjamin D Lee

Uri Neri

Simon Roux

Yuri I Wolf

Antonio Pedro Camargo

Mart Krupovic

Peter Simmonds

Nikos Kyrpides

Uri Gophna

Valerian V Dolja

Eugene V Koonin

Affiliations

Soon will be listed here.

Abstract

Viroids and viroid-like covalently closed circular (ccc) RNAs are minimal replicators that typically encode no proteins and hijack cellular enzymes for replication. The extent and diversity of viroid-like agents are poorly understood. We developed a computational pipeline to identify viroid-like cccRNAs and applied it to 5,131 metatranscriptomes and 1,344 plant transcriptomes. The search yielded 11,378 viroid-like cccRNAs spanning 4,409 species-level clusters, a 5-fold increase compared to the previously identified viroid-like elements. Within this diverse collection, we discovered numerous putative viroids, satellite RNAs, retrozymes, and ribozy-like viruses. Diverse ribozyme combinations and unusual ribozymes within the cccRNAs were identified. Self-cleaving ribozymes were identified in ambiviruses, some mito-like viruses and capsid-encoding satellite virus-like cccRNAs. The broad presence of viroid-like cccRNAs in diverse transcriptomes and ecosystems implies that their host range is far broader than currently known, and matches to CRISPR spacers suggest that some cccRNAs replicate in prokaryotes.

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