Characterization of the promoter region, first ten exons and nine intron-exon boundaries of the DNA-dependent protein kinase catalytic subunit gene, DNA-PKcs (XRCC7).

The gene, DNAPKcs (XRCC7), for the human DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a strong candidate that complements a severe combined immunodeficiency (scid) and hypersensitivity to ionizing radiation in mice. We constructed a cosmid library from a previously identified, X RCC7-covering YAC clone (943G4). From the library, we isolated three cosmid clones containing the 5'-region of XRCC7. Sequence analysis with primer walking on a 6.3-kb segment of these cosmids identified the promoter region, the first ten exons and nine intron-exon boundaries of XRCC7. The promoter region contains several potential Sp1 protein-binding sites and a high G+C content but no TATA or CCAAT boxes. These findings are consistent with the TATA-less housekeeping gene promoter and provides the basis for transcriptional regulatory studies. Since nine other exons spanning an 8-kb segment are already known, a total of 19 exons in the gene have been identified. The cosmids isolated and the primer sets designed in the present study are useful for mutation analysis in patients with a SCID phenotype.