Figure 7.

Schematic diagram showing the life-cycle of SARS-CoV-2 and the hypothetical action mechanism of the CRISPR-Cas13a system on SARS-CoV-2. The spike protein (S) binds to the host cell receptor ACE2, followed by membrane fusion and viral genome (positive-sense RNAs) release into the cytoplasm. The subgenomic RNAs are transcribed and serve as templates for mRNA synthesis. These mRNAs are then translated to generate viral structural and accessory proteins. The full‑length positive‑strand genomic RNAs are transcribed to produce full-length negative-sense genomic RNAs as templates for synthesizing new viral genome copies. The virions are assembled from the structural proteins and positive-sense genomic RNAs and are finally released outside the cell. The CRISPR-Cas13a system is activated upon binding to the target viral RNA and extensively degrades viral genomic RNAs and mRNAs, which could be used to effectively reduce viral load.