|United States Of America||Published Application||20210309981||10/07/2021||2019-011|
|European Patent Office||Published Application||3841205 A0||06/30/2021||2019-011|
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.
CRISPR, gene editing, genome, CasX, Cas12e