Scheme 1.
Chemical design of Cas9 ProSNAs and Cas9 ProSNA RNPs that enable delivery of Cas9 protein from the extracellular medium to the nucleus where it engages in genome editing. (I) Interaction with scavenger receptors on the cell surface and delivery via an endosomal pathway. (II) Disruption of endosomal membranes by GALA peptides. (III) Release of Cas9 ProSNA RNPs from the endosome. (IV) Nuclear import directed by nuclear localization signals (NLSs) of Cas9 ProSNA RNPs. (V) Targeting of genomic DNA and introduction of double-strand breaks.