|United States Of America||Issued Patent||11,118,194||09/14/2021||2016-016|
RNA-mediated adaptive immune systems in bacteria and archaea rely on Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) genomic loci and CRISPR-associated (Cas) proteins that function together to provide protection from invading viruses and plasmids. In Type II CRISPR-Cas systems, the Cas9 protein functions as an RNA-guided endonuclease that uses a dual-guide RNA consisting of crRNA and trans-activating crRNA (tracrRNA) for target recognition and cleavage by a mechanism involving two nuclease active sites that together generate double-stranded DNA breaks (DSBs). Thus, the Cas9 system provides a facile means of modifying genomic information.
UC Berkeley researchers have developed modified site-directed modifying polypeptides and ribonucleoproteins comprising the modified polypeptides. As the modified site-directed modifying polypeptides are modified for passive entry into target cells, the polypeptides are useful in a variety of methods for target nucleic acid modification.