Fig. 1: Direct detection of DNA by the CRISPR-Cas13a system. | Communications Biology

Fig. 1: Direct detection of DNA by the CRISPR-Cas13a system.

From: Harnessing noncanonical trans-cleavage characteristics of Cas12 and Cas13a to enhance CRISPR-based diagnostics

Fig. 1

a The schematic illustrates Cas13a crRNA’s recognition of ssDNA and dsDNA, initiating the trans-cleavage of a FAM/quencher-labelled RNA reporter by Cas13a. Created in BioRender (Wu, Q., 2024, BioRender.com/u87g001). b–e Evaluation of the effect of varying concentrations of ssDNA (b, c) and dsDNA (d, e) on the activation of Cas13a’s trans-cleavage activity. The ssDNA and dsDNA sequences, derived from the Hemagglutinin (H1) gene of the Influenza A virus subtype H1N1 (IVA/H1N1), can be complementarily paired and recognized by Cas13a crRNA with a 28-nucleotide spacer. Shown are the raw fluorescence intensities measured over 2 h (b, d) and the endpoint fluorescence intensities at 120 min (c, e). a.u. arbitrary units. n = 3 biologically independent experiments. In line graphs, the connecting lines represent mean values, and each circle represents an individual data point. In bar charts, error bars indicate mean ± SEM. Statistical significance was determined using unpaired two-tailed Student’s t-tests: ns (not significant, p > 0.05); *(p < 0.05); ***(p < 0.001); ****(p < 0.0001).

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