Nucleic acids researchApr 20, 2026

Accurate gene editing using a small combined GoCas12m-FokI enzyme

CRISPR Gene Editing Weekly Brief ↗PubMed ↗DOI ↗OA ↗

Updated Jun 27, 2026

Abstract

Essence

A compact GoCas12m- editor showed efficient, apparently specific genome editing at human loci in experimental systems.

Evidence

Platform experiments tested XTEN-fused GoCas12m-FokI on surrogate reporters and endogenous human targets including CLTA1, HBB, AIFM1, and ABL, reporting high-efficiency editing and no detectable off-target activity at in silico-predicted sites by targeted deep sequencing.

Caveat

Specificity was checked at predicted sites in preclinical editing assays, so genome-wide off-target risk, in vivo delivery, and therapeutic outcomes remain unproven.

Simplified

gene editing technologies have transformed functional genomics and biotechnology. Despite these advances, challenges such as limited delivery capacity and off-target activity continue to hinder their therapeutic translation. We developed a chimeric gene editing platform by fusing the compact, catalytically inactive Cas12m guiding module (GoCas12m) with the nuclease domain. GoCas12m-FokI system integrates the programmable DNA-binding capability of Cas12m with the dimerization-dependent cleavage mechanism of FokI, enabling precise genome editing. Our engineered XTEN-fused GoCas12m-FokI editor exhibits robust activity on both surrogate reporters and endogenous human loci, achieving high-efficiency editing at clinically relevant targets-including CLTA1, HBB, AIFM1, and ABL with no detectable off-target activity at in silico-predicted sites, as confirmed by targeted deep sequencing. Notably, GoCas12m-FokI is nearly half the size of conventional Cas9- or Cas12a-based editors, facilitating delivery via adeno-associated virus and other cargo-limited vectors. This dual-guided editor showed comparable editing efficiency to previously reported FokI-dCas9 systems on endogenous loci, while possessing a different PAM requirement and domain orientation. By combining compact architecture, high specificity, and modular programmability, the GoCas12m-FokI editor offers a powerful alternative for therapeutic genome editing and a promising tool for in vivo gene therapy applications.

Key numbers

6.0%

Editing Efficiency at ABL Locus

Average editing efficiency observed in K562 cells for the ABL locus.

50%

Size Comparison

Size reduction compared to conventional genome editors.

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Accurate gene editing using a small combined GoCas12m-FokI enzyme

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