Exerpt:
To inhibit RNA viruses in human cells, we used the CRISPR-Cas13d system derived from
Ruminococcus flavefaciens XPD3002, a recently discovered RNA-guided RNA
endonuclease9,10. Cas13d employs CRISPR-associated RNAs (crRNAs) that contain a
customizable 22 nucleotide (nt) spacer sequence that can direct the Cas13d protein to specific
RNA molecules for targeted RNA degradation. The high catalytic activity of Cas13d in
mammalian cells provides a potential mechanism for targeting SARS-CoV-2 for specific viral
RNA genome degradation and viral gene expression inhibition. Because of its small size (967
amino acids), high specificity, and strong catalytic activity, we chose Cas13d rather than other
Cas13 proteins to target and destroy RNA viruses including SARS-CoV-2 and Influenza A virus
(IAV)
https://www.biorxiv.org/content/10.1101/2020.03.13.991307v1.full
