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Induction and Assessment of Class Switch Recombination in Purified Murine B Cells
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Induction and Assessment of Class Switch Recombination in Purified Murine B Cells

Published on: August 13, 2010

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MBD4 Facilitates Immunoglobulin Class Switch Recombination

Fernando Grigera1, Robert Wuerffel1, Amy L Kenter2

  • 1Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, Illinois, USA.

Molecular and Cellular Biology
|November 1, 2016
PubMed

Insights

Methyl-CpG binding domain protein 4 (MBD4) is crucial for immunoglobulin class switch recombination (CSR). MBD4 deficiency impairs DNA double-strand break formation and processing, highlighting its role in the mismatch repair pathway.

Area of Science:

  • Immunology
  • Molecular Biology
  • Genetics

Background:

  • Immunoglobulin heavy chain class switch recombination (CSR) involves DNA double-strand breaks (DSBs) and repair.
  • Activation-induced cytidine deaminase (AID) initiates DSBs, requiring base excision repair (BER) and mismatch repair (MMR).
  • Methyl-CpG binding domain protein 4 (MBD4) interacts with MLH1, suggesting a role in MMR.

Purpose of the Study:

  • To investigate the role of MBD4 in CSR.
  • To determine MBD4's function in DNA double-strand break formation and processing during CSR.

Main Methods:

  • Deletion of MBD4 exons 6-8 in a B cell line.
  • Assessment of DSB formation and CSR frequency.
  • Analysis of DNA end processing and junctional sequences.

Main Results:

  • MBD4 deletion significantly reduced DSB formation and CSR frequency.
  • MBD4 deficiency resulted in DNA end processing deficits, similar to Msh2 and Mlh1 deficiencies.
  • Microhomology-rich S-S junctions were enriched in MBD4-deleted cells.

Conclusions:

  • MBD4 is essential for efficient DSB formation during CSR.
  • MBD4 functions as a component of MMR-directed DNA end processing.
  • MBD4 plays a critical role in maintaining genomic integrity during CSR.

Keywords:
B cellsIg class switchIg class switch recombinationmismatch repairuracil glycosylase

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