Long sequence insertion via CRISPR/Cas gene-editing with transposase, recombinase, and integrase

CRISPR/Cas-based gene-editing technologies have emerged as one of the most transformative tools in genome science over the past decade, providing unprecedented possibilities for both fundamental and translational research. Following the initial wave of innovations for gene knock-out, epigenetic/RNA modulation, and nickase-mediated base-editing, recent efforts have pivoted towards long-sequence gene editing—specifically, the insertion of large fragments (>1 kb) into the endogenous genome. In this review, we survey the development of these CRISPR/Cas-based sequence insertion methodologies in conjunction with the emergence of novel families of editing enzymes, such as transposases, single-stranded DNA-annealing proteins, recombinases, and integrases. Despite facing a number of challenges, this field continues to evolve rapidly and holds the potential to catalyze a new wave of revolutionary biomedical applications.