A. Cas9 cleavage at the NPM and ALK loci using the NPM1 and ALK1 gRNAs, respectively, leads to DSBs. Only the part of the gRNA that binds DNA is shown (black). PAM sequence, boxed; arrows, cleavage sites.
B. DNA ends from Cas9 cleavage that are relevant to Der5 formation are shown. NHEJ leads to a variety of Der5 translocation junctions, but a common junction (shown) is direct ligation of the DNA ends, presumably involving fill-in of the 1-base 5′ overhang.