Manganese-Powered Cas12a Enables Amplification-Free RNA Detection at Femtomolar Sensitivity
Researchers discovered that manganese ions enhance Cas12a trans-cleavage activity 60-fold for RNA targets, enabling direct, amplification-free RNA detection with femtomolar sensitivity. The mechanism is conserved across multiple Cas12a orthologues and can detect ultrashort transcripts as small as 7 nucleotides. Clinical validation on serum samples showed the platform quantitatively measured circulating miR-21 and distinguished lung cancer patients from healthy controls, matching reference clinical assays.
The original study
Direct RNA Triggering of Cas12a through the Native crRNA Architecture Enables Clinical Nucleic Acids Diagnostics.
- Authors
- Zhao X, Wang Y, Wang L, Liao S, Gong T, Xiong M, et al.
- Journal
- Analytical chemistry
- PMID
- 41870471
Original abstract
CRISPR/Cas12a has emerged as a powerful platform for nucleic acid diagnostics, yet its activity is widely considered to be restricted to DNA targets, limiting its applicability for direct RNA detection. Here we report a manganese-ion (Mn2+)-empowered Cas12a (MEC) platform that overcomes this constraint by allowing the robust RNA-mediated activation of Cas12a. Structural analyses reveal that Mn2+ strengthens RNA engagement and reorganizes the catalytic center by coordinating RNA phosphates, resulting in an enhancement of trans-cleavage efficiency by 60-fold relative to the Mg2+ conditions, without compromising sequence specificity. This Mn2+-dependent activation mechanism is conserved across multiple Cas12a orthologues (LbCas12a, AsCas12a, FnCas12a), permitting amplification-free detection of RNA with femtomolar sensitivity across diverse targets, particularly the ultrashort abortive transcripts (7 nt). Analysis of clinical serum samples further demonstrates that MEC quantitatively measures circulating miR-21 with performance concordant with reference clinical assays and effectively distinguishes lung cancer patients from healthy individuals. These results reveal an unrecognized role for Mn2+ in Cas12a biochemistry and establish a simple, versatile, and highly sensitive framework for RNA diagnostics.