Iterative crRNA design and a PAM-free strategy enabled an ultra-specific RPA-CRISPR/Cas12a detection platform

Abstract CRISPR/Cas12a is a highly promising detection tool. However, detecting single nucleotide variations (SNVs) remains challenging. Here, we elucidate Cas12a specificity through crRNA engineering and profiling of single- and double-base mismatch tolerance across three targets. Our findings indi...

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Main Authors: Xujian Mao, Jian Xu, Jingyi Jiang, Qiong Li, Ping Yao, Jinyi Jiang, Li Gong, Yin Dong, Bowen Tu, Rong Wang, Hongbing Tang, Fang Yao, Fengming Wang
Format: Article
Language:English
Published: Nature Portfolio 2024-11-01
Series:Communications Biology
Online Access:https://doi.org/10.1038/s42003-024-07173-7
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Summary:Abstract CRISPR/Cas12a is a highly promising detection tool. However, detecting single nucleotide variations (SNVs) remains challenging. Here, we elucidate Cas12a specificity through crRNA engineering and profiling of single- and double-base mismatch tolerance across three targets. Our findings indicate that Cas12a specificity depends on the number, type, location, and distance of mismatches within the R-loop. We also find that introducing a wobble base pair at position 14 of the R-loop does not affect the free energy change when the spacer length is truncated to 17 bp. Therefore, we develop a new universal specificity enhancement strategy via iterative crRNA design, involving truncated spacers and a wobble base pair at position 14 of the R-loop, which tremendously increases specificity without sacrificing sensitivity. Additionally, we construct a PAM-free one-pot detection platform for SARS-CoV-2 variants, which effectively distinguishes SNV targets across various GC contents. In summary, our work reveals new insights into the specificity mechanism of Cas12a and demonstrates significant potential for in vitro diagnostics.
ISSN:2399-3642