Gene-modified cells persist in NSG mice. (A) Gene modification rates in the bone marrow and spleen of transplanted mice at 16 weeks in cells from mice receiving either mock- or ZFN+IDLV-treated cells. High-throughput sequencing of the β-globin locus showing percentage of total aligned reads containing the modified base at the sickle mutation. Mock, open diamonds; ZFN+IDLV, closed diamonds; unpaired t test. (B) Sequencing of the β-globin locus showing insertions and deletions (indels) at the cut site as a percentage of total aligned reads. Mock, open diamonds; ZFN+IDLV, closed diamonds (n = 3 independent experiments; mock, n = 5; ZFN+IDLV, n = 12); unpaired t test. (C) Modification at the sickle base in cells from mice receiving either Oligo-, ZFN-, or ZFN+Oligo-treated cells as described in A. (D) Sequencing results for indels of cells from mice receiving either Oligo-, ZFN-, or ZFN+Oligo-treated cells as in B. Oligo, circles; ZFN, triangles; ZFN+Oligo, diamonds (Oligo, n = 8; ZFN, n = 7; ZFN+Oligo, n = 9); 1-way analysis of variance. n.s., not significant; asterisk indicates significance: *P < .05, **P < .01. Error bars, mean ± standard deviation. Values of zero cannot be plotted on a log scale but were used to calculate the error bars.