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Ku80 is required for immunoglobulin isotype switching
R Casellas1, A Nussenzweig, R Wuerffel
1Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10021, USA.
The EMBO Journal
|May 26, 1998
Summary
Ku80 is essential for antibody isotype switching, a DNA recombination process. Mice lacking Ku80 cannot complete this process, indicating DNA repair mechanisms are crucial for antibody diversification.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- Isotype switching diversifies antibody effector functions through DNA recombination.
- The precise mechanism of isotype switching remains less understood compared to V(D)J recombination.
- DNA double-strand break (DSB) repair pathways are critical in various cellular processes.
Purpose of the Study:
- To investigate the role of DNA DSB repair in antibody isotype switching.
- To determine if proteins involved in DSB repair are essential for switch recombination.
Main Methods:
- Utilized Ku80-deficient mice (Ku80(-/-)) which cannot repair DSBs.
- Reconstituted B-cell compartments in Ku80(-/-) mice by introducing specific rearranged immunoglobulin genes.
- Analyzed B-cell development, Ig gene transcription, and switch recombination in reconstituted mice.
Main Results:
- Ku80(-/-) mice reconstituted with specific B-cell genes developed mature B cells capable of initiating switch recombination.
- These B cells, however, failed to produce secondary immunoglobulin isotypes.
- Switch recombination was incomplete in the absence of functional Ku80.
Conclusions:
- Ku80 is indispensable for the completion of antibody isotype switching in vivo.
- Suggests a significant overlap in the molecular machinery for DNA DSB repair, V(D)J recombination, and isotype switching.
- Highlights the critical role of DNA repair pathways in adaptive immunity.