Correction of RAG2 gene function in RAG2^null HSPCs restores V(D)J activity and normal T cells development. (A) Percent human cells (CD45⁺ HLA A-B-C⁺) detected in spleen (SP) (22 weeks post-Tx) with coRAG2-GTed RAG2^null HSPC (0.5 x 10⁶, grey circles or 1.0 x 10⁶, red circles). HD (white circles) and uncorrected RAG2^-/- (black circles) HSPCs-derived human cells were engrafted and analyzed in parallel. (B) Human CD3⁺ T-cells detected in the spleen (SP) and (C) bone marrow (BM) derived from coRAG2-GTed RAG2^null HSPCs. (D) FACS plots showing T-cells analysis derived from 3 mice with the highest level of human CD3⁺ cells (dotted squares). Functional V(D)J rearrangement is demonstrated by the presence of CD3⁺TCR α/β, CD3⁺TCR γ/δ, and single-positive CD4⁺ and CD8⁺ derived from coRAG2-GTed RAG2^null HSPCs. (E) Treemap diversity analysis for TCRA/TCRD CDR3 sequences from sorted CD3⁺ cells from (C). Each circle is a unique CDR3 sequence, and the size of the circle represents the frequency out of the total number of reads. (F) Shannon H index score quantification of CDR3 sequence from (E-F), showing oligoclonal repertoire. Shannon index score of ≥8 indicates polyclonal repertoire. Stats. One-way ANOVA, nonparametric, Kruskal-Wallis test. Median plotted in A-C.