Modifications To Cas9 For Passive-Delivery Into Cells


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 active nuclease 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 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 helpful in a variety of methods for target nucleic acid modification.



  • Crosses the plasma membrane of a eukaryotic cell without the need for any additional agent (e.g., small molecule agents, lipids, etc.)

Potential Applications

  • Genome editing
  • Gene therapy

Contact Information

Name: Terri Sale


Phone: 510-643-4219