CRISPR RNA-guided nucleases have recently emerged as a robust genome-editing platform that functions in a wide range of organisms. To reduce off-target effects of these nucleases, we developed and validated a modified system that uses truncated guide RNAs (tru-gRNAs). The use of tru-gRNAs leads to decreases in off-target effects and does not generally compromise the on-target efficiencies of these genome-editing nucleases. In this chapter, we describe guidelines for identifying potential tru-gRNA target sites and protocols for measuring the on-target efficiencies of CRISPR RNA-guided nucleases in human cells.
Keywords: CRISPR RNA-guided nucleases; CRISPR/Cas nucleases; Cas9; Genome editing; Off-target effects; Off-target mutations; Truncated guide RNAs.