Efficient TALEN-mediated editing of GR gene in the T2 cell line. (A) Schematic representation of the GR genomic locus (chromosome 5q31-q32) and TALEN-targeted sequence (exon 2). (B) T7 endonuclease I assay showing efficient nonhomologous end joining recombination–mediated mutagenesis (60%) at the intended target site on the GR gene. mRNA (10 μg) from each TALEN was used to transfect the T2 cell line with a BTX AgilePulse electroporator. At day 3, the genomic DNA was amplified by polymerase chain reaction and subjected to a mismatch-sensitive T7 endonuclease I digestion, prior to a separation on a 10% polyacrylamide Tris-borate-EDTA gel. Gene modification (indels) quantification was based on relative band intensities (ImageJ). (C) Representative sequences of the human GR on targeted site using MiSeq analysis. (D) Western blot analysis of TALEN and GR expression before and after DEX enrichment of mutated cells. At day 3, the T2^GR-Ex2 (TALEN-modified) cells were treated with DEX (10⁻⁴ M) for 7 days. COOH, carboxylic acid; D, digested; ND, nondigested; NH2, amidogen.