Immunoglobulin kappa light chain gene rearrangement is impaired in mice deficient for DNA polymerase mu

Immunity. 2003 Aug;19(2):203-11. doi: 10.1016/s1074-7613(03)00203-6.


DNA polymerase mu (pol mu) is a template-dependent polymerase closely related to the lymphoid-specific enzyme terminal deoxynucleotidyl transferase (TdT). We report here the phenotype of pol mu-deficient mice. Such animals display an abnormal B cell differentiation, with a specific alteration in the IgM- to IgM+ transition in bone marrow. In all mice, Ig light chain gene rearrangement is impaired at the level of the Vkappa-Jkappa and Vlambda-Jlambda junctions, which show extensive nibbling of both coding extremities. These alterations lead to a profound defect in the peripheral B cell compartment which, although variable between animals, results in an average 40% reduction in the splenic B cell fraction. Pol mu appears, therefore, as a key element contributing to the relative homogeneity in size of light chain CDR3 and taking part in Ig gene rearrangement at a stage where TdT is no longer expressed.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • B-Lymphocytes / enzymology
  • B-Lymphocytes / immunology
  • B-Lymphocytes / pathology
  • Base Sequence
  • Complementarity Determining Regions
  • DNA, Complementary / genetics
  • DNA-Directed DNA Polymerase / deficiency*
  • DNA-Directed DNA Polymerase / genetics
  • Gene Rearrangement, B-Lymphocyte, Light Chain*
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Phenotype
  • Species Specificity
  • Tissue Distribution


  • Complementarity Determining Regions
  • DNA, Complementary
  • DNA polymerase mu
  • DNA-Directed DNA Polymerase