A eukaryotic genome editor; plus a B cell checkpoint target for cancer and more

Feng Zhang and colleagues at the Broad Institute of MIT and Harvard described in Nature a eukaryotic RNA-guided DNA endonuclease, Fanzor, and programmed it for human genome engineering. Fanzor enzymes are encoded in the eukaryotic genome within transposable elements, and use nearby non-coding RNAs to target specific genomic sites. Because the Fanzor systems are more compact than CRISPR-Cas systems, they may be amenable to a wider range of delivery vectors.

In 2021, Zhang's group published a Science study characterizing a new class of transposon-encoded, RNA-guided DNA nucleases from prokaryotes, dubbed Obligate Mobile Element Guided Activity (OMEGA); one of these nucleases, TnpB, is a likely ancestor of both Fanzor and Cas12. Unlike Cas12, Fanzor did not show collateral activity against single stranded DNA, or other nucleic acid classes...