The C-terminal conserved domain of DNA-PKcs, missing in the SCID mouse, is required for kinase activity
- 1 April 2000
- journal article
- Published by Oxford University Press (OUP) in Nucleic Acids Research
- Vol. 28 (7) , 1506-1513
- https://doi.org/10.1093/nar/28.7.1506
Abstract
DNA-PKcs, the catalytic subunit of DNA-dependent protein kinase (DNA-PK), has a phosphoinositol 3-kinase (PI 3-K) domain close to its C-terminus. Cell lines derived from the SCID mouse have been utilised as a model DNA-PKcs-defective system. The SCID mutation results in truncation of DNA-Pkcs at the extreme C-terminus leaving the PI 3-K domain intact. The mutated protein is expressed at low levels in most SCID cell lines, leaving open the question of whether the mutation abolishes kinase activity. Here, we show that a SCID cell line that expresses the mutant protein normally has dramatically impaired kinase activity. We estimate that the residual kinase activity typically present in SCID fibroblast cell lines is at least two orders of magnitude less than that found in control cells. Our results substantiate evidence that DNA-PKcs kinase activity is required for DSB rejoining and V(D)J recombination and show that the extreme C-terminal region of DNA-PKcs, present in PI 3-K-related protein kinases but absent in bona fide PI 3 lipid kinases, is required for DNA-PKcs to function as a protein kinase. We also show that expression of mutant DNA-PKcs protein confers a growth disadvantage, providing an explanation for the lack of DNA-PKcs expression in most SCID cell lines.Keywords
This publication has 44 references indexed in Scilit:
- Murine Cell Line SX9 Bearing a Mutation in the dna-pkcsGene Exhibits Aberrant V(D)J Recombination Not Only in the Coding Joint but Also in the Signal JointJournal of Biological Chemistry, 1998
- Identification of a nonsense mutation in the carboxyl-terminal region of DNA-dependent protein kinase catalytic subunit in the scid mouse.Proceedings of the National Academy of Sciences, 1996
- Ku86-Deficient Mice Exhibit Severe Combined Immunodeficiency and Defective Processing of V(D)J Recombination IntermediatesCell, 1996
- Requirement for Ku80 in growth and immunoglobulin V(D)J recombinationNature, 1996
- PIK-Related Kinases: DNA Repair, Recombination, and Cell Cycle CheckpointsScience, 1995
- Defective DNA-dependent protein kinase activity is linked to V(D)J recombination and DNA repair defects associated with the murine scid mutationCell, 1995
- The SCID Mouse Mutant: Definition, Characterization, and Potential UsesAnnual Review of Immunology, 1991
- The scid mutation in mice causes a general defect in DNA repairNature, 1990
- Cell Cycle Responses of Two X-ray Sensitive Mutants Defective in DNA RepairInternational Journal of Radiation Biology, 1989
- A severe combined immunodeficiency mutation in the mouseNature, 1983