1. DNA-dependent Protein Kinase Activity Is Not Required for Immunoglobulin Class Switching
- Author
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Gayle C. Bosma, Maria G. Cotticelli, Donna M. Fath, Jiyoon Kim, Marko Z. Radic, Teresa Urich, Norman R. Ruetsch, and Melvin J. Bosma
- Subjects
Lipopolysaccharides ,DNA Repair ,DNA repair ,T-Lymphocytes ,Immunology ,chemical and pharmacologic phenomena ,DNA-Activated Protein Kinase ,Mice, SCID ,Biology ,Protein Serine-Threonine Kinases ,medicine.disease_cause ,Ig transgenes ,B cell anergy ,Immunoglobulin Class Switch Recombination ,Article ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Transforming Growth Factor beta ,medicine ,Immune Tolerance ,Immunology and Allergy ,Animals ,Protein kinase A ,030304 developmental biology ,Recombination, Genetic ,0303 health sciences ,Ku70 ,Mutation ,Severe combined immunodeficiency ,B-Lymphocytes ,Mice, Inbred BALB C ,Genes, Immunoglobulin ,medicine.disease ,Molecular biology ,scid B cells ,Immunoglobulin Class Switching ,3. Good health ,nonhomologous end joining ,Immunoglobulin A ,Non-homologous end joining ,DNA-Binding Proteins ,Immunoglobulin class switching ,Immunoglobulin G ,Interleukin-4 ,030215 immunology - Abstract
Class switch recombination (CSR), similar to V(D)J recombination, is thought to involve DNA double strand breaks and repair by the nonhomologous end–joining pathway. A key component of this pathway is DNA-dependent protein kinase (DNA-PK), consisting of a catalytic subunit (DNA-PKcs) and a DNA-binding heterodimer (Ku70/80). To test whether DNA-PKcs activity is essential for CSR, we examined whether IgM+ B cells from scid mice with site-directed H and L chain transgenes were able to undergo CSR. Although B cells from these mice were shown to lack DNA-PKcs activity, they were able to switch from IgM to IgG or IgA with close to the same efficiency as B cells from control transgenic and nontransgenic scid/+ mice, heterozygous for the scid mutation. We conclude that CSR, unlike V(D)J recombination, can readily occur in the absence of DNA-PKcs activity. We suggest nonhomologous end joining may not be the (primary or only) mechanism used to repair DNA breaks during CSR.
- Published
- 2002