What strategies enable efficient multiplex gene editing?

Multiplex editing strategies include: expressing multiple gRNAs from single plasmid using tRNA spacers (processed by endogenous RNases), U6/H1 tandem promoters, or Csy4-processed arrays; using orthogonal Cas proteins (SpCas9, SaCas9, Cas12a) for different targets simultaneously; self-processing ribozyme-flanked guides; and polycistronic gRNA constructs. For large-scale multiplexing (10+ edits), iterative editing rounds with selection, MAGE (Multiplex Automated Genome Engineering) for bacterial systems, or prime editing for multiple simultaneous changes. Challenges include managing off-target accumulation, ensuring efficient delivery of multiple components, and potential chromosomal rearrangements from multiple DSBs. Applications include pathway engineering, model organism generation, and synthetic genome construction.