Programmable ribozyme enables RNA signal transduction

The manuscript presents UNBAR, a programmable, RNA-triggered dual-site self-cleaving ribozyme encoded in a single RNA strand that can detect specific RNA triggers and release functional non-coding RNA effectors. The authors report cell-free sensing and protein-free amplification of microRNA and viral RNA, and demonstrate trigger-dependent regulation of CRISPR-Cas9 in zebrafish embryos and human cells.

The authors describe engineering a programmable, RNA-triggered, dual-site self-cleaving ribozyme called UNBAR. It is encoded within a single RNA strand and combines a modular sensing domain with a modular cleavage product. The design can be largely inactive in the absence of its trigger and can be tuned for single-nucleotide trigger specificity. The manuscript is provided as an unedited early-access version and will undergo further editing before final publication. Key findings: - UNBAR is a dual-site self-cleaving ribozyme fully encoded on one RNA strand with separate sensing and output modules. - The ribozyme can be designed to be almost completely inactive without its trigger and to distinguish single-nucleotide differences in trigger RNA. - Trigger-dependent cleavage can release non-coding RNA effectors including sgRNA, shRNA and aptamer sequences. - The system performs cell-free sensing and protein-free amplification of microRNA and viral RNA, with a cleaved aptamer fluorescence readout demonstrated. - Engineered variants function in cells and the authors report trigger-dependent regulation of CRISPR-Cas9 editing in zebrafish embryos and human cells. Summary: The paper reports UNBAR as a first-in-class, programmable modality for transducing RNA triggers into functional RNA outputs, described across cell-free and cellular contexts. The authors present applications from molecular sensing to regulation of CRISPR-Cas9 and note that the manuscript is an unedited early-access version that will undergo further editing prior to final publication.