TREX2-FrCas9 Nuclease

Product Introduction

TREX2-FrCas9 is an engineered protein created by fusing FrCas9 with Three-prime Repair Exonuclease 2 (TREX2). By introducing exonuclease activity, it significantly alters the DNA repair outcomes produced by the CRISPR-Cas9 system. TREX2 is an exonuclease with 3'→5' directionality that progressively digests nucleotides from DNA double-strand break ends. When fused with FrCas9, it can generate larger fragment deletions at the cleavage site.

Traditional CRISPR-Cas9 systems, after introducing DNA double-strand breaks, rely on the cellular non-homologous end joining (NHEJ) pathway for repair, which typically results in small insertion or deletion mutations (mostly less than 10 bp). This small-scale editing may be insufficient to completely disrupt gene function for certain applications, particularly those targeting non-coding RNAs, regulatory elements, or protein domains with structural functions. The TREX2-FrCas9 fusion protein overcomes this limitation: after FrCas9 generates a double-strand break at the target site, the fused TREX2 immediately performs 3'→5' exonucleolytic digestion on the broken ends, enlarging the gap and forcing the cell to produce significantly larger deletions (up to hundreds of base pairs) during NHEJ repair.