The Klra gene cluster of Klra15-targeted (mutant) mice contains a concatemer insertion of the Klra15-targeting construct. (A) A schematic representation of the natural killer gene complex (NKC) and the targeting-construct produced for the Klra15 gene. (B) Southern blot analysis of wild-type (WT) and mutant thymus DNA digested with EcoRI, KpnI, or BamHI and probed with the Klra15-targeting construct depicted in panel A. (C) Array comparative genomic hybridization profile of the Klra cluster in mutant mice with a blow-up of the Klra15 gene (below). The x-axis represents the genomic region tiled on the microarrays, and the y-axis Shows differences in copy number between WT and mutant genomic DNA (log₂ ratio [MT/WT]). Positive values indicate regions showing copy number increases in the NKC knockdown (NKC^KD) genome. (D) PCR analysis of the Klra15-targeting construct copy number in mutant genomic DNA. Data are representative of ≥ 3 similar experiments, except for array comparative genomic hybridization analysis, which was performed twice. These experiments were performed with mice on the 129S1 background.