FIGURE 5.

CRISPR/Cas13a-based knockdown and RNA base editing in transgenic plant development. (A) The CRISPR/Cas13a system can be used to degrade specific ssRNAs due to the presence of two higher eukaryotic and prokaryotic nucleotide-binding endo-RNase domains and the absence of a DNase catalytic site. (B) The dCas13a nuclease (with RNAse domains mutated) can be fused to specific deaminase domains to promote single-base editing. So far, the deaminase domain most successfully fused to the Cas13a nuclease was that of an adenosine deaminase (ADA), specifically, the ADAR2 domain, which is capable of converting adenosine (A) to inosine (I), which in turn is recognized as guanine (G) by the translation machinery, in ssRNA molecules.