Disruption of endogenous genes by direct delivery of TALEN proteins. (A) Frequency of endogenous CCR5 gene disruption in HeLa cells and hiPSCs subjected to three consecutive treatments with TALEN proteins as determined by the Surveyor assay. Surveyor nuclease cleavage at mismatches produces products of 254 bp and 277 bp. (B) Representative sequence analysis of the CCR5 locus in HeLa cells after three consecutive treatments with 3 μM TAT-TALEN proteins under hypothermic conditions. Multiple deletions (dashed) and insertions (lowercase) are aligned with the cleavage site (wild type [WT]). Underlines highlight binding sites for TALEN L and TALEN R.