CasX Nickase Designs, Tans Cleavage Designs & Structure

Tech ID: 29659 / UC Case 2019-011-0

Patent Status

Country Type Number Dated Case
United States Of America Published Application 20210309981 10/07/2021 2019-011
European Patent Office Published Application 3841205 A0 06/30/2021 2019-011

Brief Description

Metagenomic analysis of microbial DNA from groundwater samples revealed a new protein, CasX, that prevented bacterial transformation by plasmid DNA when expressed with cognate crRNAs targeting the plasmid8. Sequence analysis of CasXrevealed no similarity to other CRISPR-Cas enzymes, except for the presence of a RuvC nuclease domain similar to that found in both Cas9 and Cas12a enzyme families as well as transposases and recombinases. The evolutionary ambiguity of CasX hinted at a distinct structure and mechanism for DNA targeting, but without reconstitution of a functional CasX enzyme it was not possible to determine its

mechanism of plasmid interference.


UC Berkeley inventors found variant CasX polypeptides that induce programmable, site-specific genome repression in E. coli and genome editing in human cells, distinct from Cas9 and Cas12a, which establishes this enzyme family as a third CRISPR-Cas system for genetic manipulation.

Suggested uses

  • Genome editing
  • Gene therapy
  • Research tools
  • Genomic imaging


  • Functions under different conditions than currently used CRISPR-Cas proteins
  • Nucleotide sequence encoding the CasX is short, therefore especially useful when using a viral vector for deliver to cell

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  • Doudna, Jennifer A.

Other Information


CRISPR, gene editing, genome, CasX, Cas12e

Categorized As

Additional Technologies by these Inventors