FIG 4.

CRISPR-Cas12a-mediated direct detection of SARS-CoV-2 mutations. (A) Schematic of the SARS-CoV-2 Orf8 gene and the mutation for S and L lineage of SARS-CoV-2. The sequences and positions of the target gene ORF8, the guide RNA crRNA-Orf8, and the protospacer adjacent motif (PAM) are indicated. (B) Fluorescence was measured at different time points using 10¹¹ copies/μl plasmid DNA of SARS-CoV-2 L and S lineage as the template. Assay specificity was validated with nucleic acid samples of nucleic acid samples of common human coronavirus (HCoV) 229E, HCoV OC43, and HCoV HKU1, rhinovirus (HRV), adenovirus (ADV), respiratory syncytial virus (RSV) A and B, human bocavirus (HBoV), human metapneumovirus (HMPV), human parainfluenza virus (HPIV-1 and HPIV-4) and Mycoplasma pneumoniae, as well as HIV-1, HBV, HCV, Chlamydia trachomatis, and Treponema pallidum. The mean value of fluorescence of three independent experiments is presented. No input indicates negative control of no plasmid DNA.