374: DNA-guided Cas12a reprogrammed to target RNA

Wu X et al., Nature Biotechnology - The authors engineer synthetic PAM-containing DNA guides (crDNA) that bind Cas12a to form a deoxyribonucleoprotein (DNP) complex that recognizes and cleaves complementary RNA. Structural, biochemical and cellular data define a PAM-dependent activation route distinct from canonical RNA-guided systems and demonstrate applications in sensitive diagnostics and intracellular RNA knockdown. Key terms: DNA-guided Cas12a, crDNA, RNA targeting, SLEUTH diagnostic, RNA knockdown. Study Highlights:The team designed single-stranded PAM-bearing crDNA that assembles with Cas12a to form a stable DNP complex and recruit complementary RNA substrates. Cryo-EM and modeling show crDNA occupies the PI/WED/REC groove, preserves PAM engagement and positions an RNA–DNA heteroduplex for RuvC-mediated cleavage. DNA-guided Cas12a selectively binds and cleaves ssRNA, enables robust trans-cleavage across targets and orthologs, and supports an amplification-coupled SLEUTH diagnostic with attomolar sensitivity. In cells, phosphorothioate-stabilized crDNA with Cas12a produced sequence-specific knockdown of reporter and endogenous transcripts with minimal off-target signal. Conclusion:Cas12a can be reprogrammed into a DNA-guided, RNA-targeting effector: PAM-mediated crDNA engagement forms a catalytically competent complex that achieves sequence-specific RNA cleavage, enabling a new architecture for diagnostics and a proof-of-concept for intracellular RNA knockdown while highlighting stability and optimization challenges. Music:Enjoy the music based on this article at the end of the episode. Article title:DNA-guided CRISPR–Cas12a effectors for programmable RNA recognition and cleavage First author:Wu X Journal:Nature Biotechnology DOI:10.1038/s41587-026-03120-5 Reference:Wu X., Lam W.H., Zhao Z., Feng X., Zhai Y., Hsing I.-M. DNA-guided CRISPR–Cas12a effectors for programmable RNA recognition and cleavage. Nature Biotechnology (2026). doi:10.1038/s41587-026-03120-5 License:This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/ Support:Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00 Official website https://basebybase.com On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics. Episode link: https://basebybase.com/episodes/dna-guided-cas12a-reprogrammed-to-target-rna QC:This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-05-22. QC Scope:- article metadata and core scientific claims from the narration- excludes analogies, intro/outro, and music- transcript coverage: Audited transcript sections describing crDNA design and PAM activation, structural data from cryo-EM, RNA targeting and cleavage mechanics, SLEUTH diagnostic workflow and performance, and intracellular RNA knockdown in cells.- transcript topics: DNA-guided Cas12a concept and crDNA design; PAM-dependent activation and DNP formation; Cryo-EM structure and DNA–RNA duplex within Cas12a; Two-step binding kinetics (Kd1 and Kd2); Trans-cleavage activity and RNA targeting kinetics; SLEUTH diagnostic workflow and performance QC Summary:- factual score: 10/10- metadata score: 10/10- supported core claims: 8- claims flagged for review: 0- metadata checks passed: 4- metadata issues found: 0 Metadata Audited:- article_doi- article_title- article_journal- license Factual Items Audited:- DNA-guided Cas12a can target RNA using crDNA with PAM-dependent activation- crDNA occupies PAM-inte...