A targeted DNA-PKcs-null mutation reveals DNA-PK-independent functions for KU in V(D)J recombination

Immunity. 1998 Sep;9(3):367-76. doi: 10.1016/s1074-7613(00)80619-6.

Abstract

The DNA-dependent protein kinase (DNA-PK) consists of Ku70, Ku80, and a large catalytic subunit, DNA-PKcs. Targeted inactivation of the Ku70 or Ku80 genes results in elevated ionizing radiation (IR) sensitivity and inability to perform both V(D)J coding-end and signal (RS)-end joining in cells, with severe growth retardation plus immunodeficiency in mice. In contrast, we now demonstrate that DNA-PKcs-null mice generated by gene-targeted mutation, while also severely immunodeficient, exhibit no growth retardation. Furthermore, DNA-PKcs-null cells are blocked for V(D)J coding-end joining, but retain normal RS-end joining. Finally, while DNA-PK-null fibroblasts exhibited increased IR sensitivity, DNA-PKcs-deficient ES cells did not. We conclude that Ku70 and Ku80 may have functions in V(D)J recombination and DNA repair that are independent of DNA-PKcs.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigens, Nuclear*
  • DNA Helicases*
  • DNA-Activated Protein Kinase
  • DNA-Binding Proteins / physiology*
  • Embryo, Mammalian
  • Female
  • Fibroblasts / enzymology
  • Fibroblasts / radiation effects
  • Gene Rearrangement, B-Lymphocyte, Heavy Chain / genetics*
  • Gene Targeting*
  • Immunoglobulin Joining Region / genetics
  • Ku Autoantigen
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mutation / genetics
  • Nuclear Proteins / physiology*
  • Phenotype
  • Protein-Serine-Threonine Kinases / biosynthesis
  • Protein-Serine-Threonine Kinases / genetics*
  • Protein-Serine-Threonine Kinases / physiology
  • Radiation, Ionizing
  • Severe Combined Immunodeficiency / genetics
  • Signal Transduction
  • Stem Cells / enzymology
  • Stem Cells / metabolism
  • Stem Cells / physiology
  • Stem Cells / radiation effects
  • Thymus Gland / cytology
  • Thymus Gland / physiology

Substances

  • Antigens, Nuclear
  • DNA-Binding Proteins
  • Immunoglobulin Joining Region
  • Nuclear Proteins
  • DNA-Activated Protein Kinase
  • Protein-Serine-Threonine Kinases
  • DNA Helicases
  • XRCC5 protein, human
  • Xrcc6 protein, human
  • Xrcc6 protein, mouse
  • Ku Autoantigen