FnCas9 based CRISPR diagnostic for rapid and accurate detection of major SARS-CoV2 variants on a paper strip
- CSIR Institute of Genomics and Integrative Biology, India
- CSIR-Institute of Genomics and Integrative Biology, India
Abstract
The COVID-19 pandemic originating in the Wuhan province of China in late 2019 has impacted global health, causing increased mortality among elderly patients and individuals with comorbid conditions. During the passage of the virus through affected populations, it has undergone mutations, some of which have recently been linked with increased viral load and prognostic complexities. Several of these variants are point mutations that are difficult to diagnose using the gold standard quantitative real-time PCR (qRT-PCR) method and necessitates widespread sequencing which is expensive, has long turn-around times, and requires high viral load for calling mutations accurately. Here, we repurpose the high specificity of Francisella novicida Cas9 (FnCas9) to identify mismatches in the target for developing a lateral flow assay that can be successfully adapted for the simultaneous detection of SARS-CoV2 infection as well as for detecting point mutations in the sequence of the virus obtained from patient samples. We report the detection of the S gene mutation N501Y (present across multiple variant lineages of SARS-CoV2) within an hour using lateral flow paper strip chemistry. The results were corroborated using deep sequencing on multiple wild type (n=37) and mutant (n=22) viral RNA samples with a sensitivity of 87% and specificity of 97%. The design principle can be rapidly adapted for other mutations (as shown also for E484K and T716I) highlighting the advantages of quick optimization and roll-out of CRISPR diagnostics (CRISPRDx) for disease surveillance even beyond COVID-19. This study was funded by Council for Scientific and Industrial Research, India.
Data availability
Sequencing data associated with the manuscript have been deposited to GISAID with the following numbers:EPI_ISL_911542, EPI_ISL_911532, EPI_ISL_911543, EPI_ISL_911533, EPI_ISL_911544, EPI_ISL_911534, EPI_ISL_911545, EPI_ISL_911535, EPI_ISL_911546, EPI_ISL_911536, EPI_ISL_911547, EPI_ISL_911537, EPI_ISL_911538, EPI_ISL_911540, EPI_ISL_911541, EPI_ISL_911539 were just released and are now available to all participants in GISAID.
Article and author information
Author details
Janani Srinivasa Vasudevan
Debojyoti Chakraborty
Funding
University Grants Commission (Graduate student fellowship)
- Manoj Kumar
IUSSTF (CLP-0033)
- Rajesh Pandey
CSIR Sickle Cell Anemia Mission (HCP0008)
- Debojyoti Chakraborty
Tata Steel (SSP 2001)
- Debojyoti Chakraborty
Lady Tata Young Investigator (GAP0198)
- Debojyoti Chakraborty
CSIR Sickle Cell Anemia Mission (HCP0008)
- Souvik Maiti
CSIR (Graduate Student fellowship)
- Mohd Azhar
CSIR (Graduate Student fellowship)
- Jayaram Murthy
CSIR (Research Associateship)
- Sneha Gulati
Indian Council of Medical Research (Graduate Student fellowship)
- Asgar H Ansari
CSIR (Graduate Student fellowship)
- Rhythm Phutela
CSIR (Graduate Student fellowship)
- Sundaram Acharya
CSIR (Research Associateship)
- Poorti Kathpalia
CSIR (MLP 2005)
- Rajesh Pandey
Fondation Botnar (CLP-0031)
- Rajesh Pandey
Intel Corporation (CLP-0034)
- Rajesh Pandey
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: The present study was approved by the Ethics Committee, Institute of Genomics and Integrative Biology, New Delhi (CSIR-IGIB/IHEC/2020-21/01.)
Copyright
© 2021, Kumar et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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FnCas9 based CRISPR diagnostic for rapid and accurate detection of major SARS-CoV2 variants on a paper strip
eLife 10:e67130.
https://doi.org/10.7554/eLife.67130
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