Fig. 1.

CRISPR target sequences in the ROSA26Sor locus. The CRISPR target sequences in the first intron of ROSA26 locus were searched through the UCSC genome browser available through genome-engineering.org/tools (Zhang lab). The results displayed 14 target sequences, of which 4 were within the vicinity of ∼270 bases from the XbaI site, the most commonly used site for targeted insertion of foreign sequences at this locus. These four target sites were named as ROSA Cr1, Cr2, Cr3 and Cr4 and only the Cr2 and Cr4 sites were tested in this study. The cut sites are indicated by a forward slash (/) and PAM sequences are underlined.