Homozygous DNA ligase IV R278H mutation in mice leads to leaky SCID and represents a model for human LIG4 syndrome

Proc Natl Acad Sci U S A. 2010 Feb 16;107(7):3024-9. doi: 10.1073/pnas.0914865107. Epub 2010 Feb 1.


DNA ligase IV (LIG4) is an essential component of the nonhomologous end-joining (NHEJ) repair pathway and plays a key role in V(D)J recombination. Hypomorphic LIG4 mutations in humans are associated with increased cellular radiosensitivity, microcephaly, facial dysmorphisms, growth retardation, developmental delay, and a variable degree of immunodeficiency. We have generated a knock-in mouse model with a homozygous Lig4 R278H mutation that corresponds to the first LIG4 mutation reported in humans. The phenotype of homozygous mutant mice Lig4(R278H/R278H) (Lig4(R/R)) includes growth retardation, a decreased life span, a severe cellular sensitivity to ionizing radiation, and a very severe, but incomplete block in T and B cell development. Peripheral T lymphocytes show an activated and anergic phenotype, reduced viability, and a restricted repertoire, reminiscent of human leaky SCID. Genomic instability is associated with a high rate of thymic tumor development. Finally, Lig4(R/R) mice spontaneously produce low-affinity antibodies that include autoreactive specificities, but are unable to mount high-affinity antibody responses. These findings highlight the importance of LIG4 in lymphocyte development and function, and in genomic stability maintenance, and provide a model for the complex phenotype of LIG4 syndrome in humans.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abnormalities, Multiple / genetics*
  • Animals
  • Antibody Formation / genetics*
  • Apoptosis / immunology
  • Blotting, Southern
  • Child
  • DNA Ligase ATP
  • DNA Ligases / genetics*
  • DNA Ligases / immunology
  • Developmental Disabilities / genetics*
  • Disease Models, Animal*
  • Flow Cytometry
  • Humans
  • Immunoglobulins / blood
  • Immunophenotyping
  • Mice
  • Mutation, Missense / genetics*
  • Mutation, Missense / immunology
  • Severe Combined Immunodeficiency / genetics*
  • Syndrome


  • Immunoglobulins
  • LIG4 protein, human
  • DNA Ligases
  • DNA Ligase ATP