A Tale of Two Moieties: Rapidly Evolving CRISPR/Cas-Based Genome Editing

Two major moieties in genome editing are required for precise genetic changes: the locator moiety for target binding and the effector moiety for genetic engineering. By taking advantage of CRISPR/Cas, which consists of different modules for indepen- dent target binding and cleavage, a spectrum of precise and versatile genome editing technologies have been developed for broad applications in biomedical re- search, biotechnology, and therapeutics. Here, we briefly summarize the progress of genome editing systems from a view of both locator and effector moieties and highlight the advance of newly reported CRISPR-conjugated base editing and prime editing systems. We also underscore distinct mechanisms of off-target effects in CRISPR-conjugated systems and further discuss possible strategies to reduce off-target mutations in the future.