Nonsense mutation at Tyr-4046 in the DNA-dependent protein kinase catalytic subunit of severe combined immune deficiency mice

Abstract

The severe combined immune deficiency (SCID) mouse was reported as an animal model for human immune deficiency. Through the course of several studies, the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) gene came to be considered a candidate for the SCIDresponsible gene. We isolated an ORF of the murine DNAPKcs gene from SCID mice and their parent strain C.B-17 mice and determined the DNA sequences. The ORF of the murine DNA-PKcs gene contained 4128-aa residues and had 78.9% homology with the human DNA-PKcs gene. A particularly important finding is that a T to A transversion results in the substitution of termination codon in SCID mice for the Tyr-4046 in C.B-17 mice. No other mutation was detected in the ORF of the gene. The generality of this transversion was confirmed using four individual SCID and wild-type mice. The substitution took place in the phosphatidylinositol 3-kinase domain, and the mutated gene encodes the truncated products missing 83 residues of wild-type DNA-PKcs products. Furthermore, the quantity of DNA-PKcs transcript in wild-type and SCID cells was almost equal. These observations indicate that the DNA-PKcs gene is the SCID-responsible gene itself and that the detected mutation leads to the SCID aberration.

Brief Report: Impaired Cell Reprogramming in Nonhomologous End Joining Deficient Cells

“…2G). Additionally, we demonstrated that, as with parental Prkdc scid MEFs, Prkdc scid Tn-iPSCs were also hypersensitive to ionizing radiation as expected for cells deficient in NHEJ [22][23][24] (Fig. 2H).…”

Improved efficacy of gene therapy approaches for Pompe disease using a new, immune-deficient GSD-II mouse model

“…This was achieved by interbreeding GAA-KO mice 16 with SCID mice, 17,18 yielding GAA-KO/SCID mice. Since these mice are immune-deficient, they will not allow the assessment of adaptive (cytotoxic) immune responses to the vector.…”

“…17,18 The original GAA-KO mice were produced by targeted disruption of exon 6 of the murine GAA gene by insertion of neomyocin resistance gene (Figure 1a), the resulting homozygous 6 neo /6 neo GAAKO mice have barely detectable GAA transcripts, and no GAA protein product can be detected in their muscle tissues. 16 Immuno-deficient SCID mice have a spontaneous point mutation in the catalytic subunit of DNA-dependent protein kinase (DNA-PKc) gene (Figure 1b), resulting in the inability of T-and B-lymphocytes to mature.…”

“…16 Immuno-deficient SCID mice have a spontaneous point mutation in the catalytic subunit of DNA-dependent protein kinase (DNA-PKc) gene (Figure 1b), resulting in the inability of T-and B-lymphocytes to mature. 17,18 Interbreeding GAA-KO mice with SCID mice gave rise to F1 double heterozygote mice, designated as GAA+/ ÀSCID+/À. Intercrossing F1 progeny allowed for isolation of double knock out GAA-KO/SCID mice.…”

“…17,18 The F1 generation of the offspring was heterozygous at both the murine GAA and SCID locus, and was designated as GAA-KO+/ÀSCID+/À. F1 mice were intercrossed and all offspring were genotyped to identify GAA-KOÀ/ÀSCIDÀ/À offspring, which we refer to here as GAA-KO/SCID mice.…”