Nucleic Acid Enzyme-Activated CRISPR-Cas12a With Circular CRISPR RNA for Biosensing |
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Authors: | Yunping Wu Dingran Chang Yangyang Chang Qiang Zhang Yi Liu John D Brennan Yingfu Li Meng Liu |
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Affiliation: | 1. School of Environmental Science and Technology, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), Dalian University of Technology, Dalian POCT Laboratory, Dalian, 116024 China;2. Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S4K1 Canada;3. School of Bioengineering, Dalian University of Technology, Dalian, 116024 China;4. Department of Neurology, Dalian Municipal Central Hospital, Affiliated Hospital of Dalian Medical University, Dalian, 116033 China;5. Biointerfaces Institute, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S4O3 Canada |
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Abstract: | clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems are increasingly used in biosensor development. However, directly translating recognition events for non-nucleic acid targets by CRISPR into effective measurable signals represents an important ongoing challenge. Herein, it is hypothesized and confirmed that CRISPR RNAs (crRNAs) in a circular topology efficiently render Cas12a incapable of both site-specific double-stranded DNA cutting and nonspecific single-stranded DNA trans cleavage. Importantly, it is shown that nucleic acid enzymes (NAzymes) with RNA-cleaving activity can linearize the circular crRNAs, activating CRISPR-Cas12a functions. Using ligand-responsive ribozymes and DNAzymes as molecular recognition elements, it is demonstrated that target-triggered linearization of circular crRNAs offers great versatility for biosensing. This strategy is termed as “NAzyme-Activated CRISPR-Cas12a with Circular CRISPR RNA (NA3C).” Use of NA3C for clinical evaluation of urinary tract infections using an Escherichia coli-responsive RNA-cleaving DNAzyme to test 40 patient urine samples, providing a diagnostic sensitivity of 100% and specificity of 90%, is further demonstrated. |
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Keywords: | aptazymes CRISPR-Cas12a deoxyribozymes pathogenic bacterias ribozymes |
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