Huwe1 supports B-cell development, B-cell-dependent immunity, somatic hypermutation and class switch recombination by...

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• B-cell development and immunoglobulin gene diversification are vital for adaptive immunity.
• The ubiquitin E3 ligase HUWE1 regulates cell proliferation and DNA repair pathways.
• HUWE1's role in B-cell specific processes like somatic hypermutation (SHM) and class switch recombination (CSR) requires further investigation.

Purpose of the Study:

• To investigate the role of HUWE1 in B-cell proliferation and immunoglobulin gene diversification.
• To determine HUWE1's involvement in SHM and CSR.
• To elucidate the mechanisms by which HUWE1 influences B-cell activation and maturation.

Main Methods:

• B-cell-specific deletion of the Huwe1 gene in mice.
• In vitro and in vivo analyses of B-cell development, proliferation, SHM, and CSR.
• Assessment of activation-induced cytidine deaminase (AID) expression and Myc target gene output.

Main Results:

• B-cell-specific deletion of Huwe1 impaired B-cell development, differentiation, and maturation.
• HUWE1 deficiency diminished SHM and CSR by reducing B-cell proliferation and AID expression.
• HUWE1's role in these processes was independent of its regulation of base excision repair (BER).
• HUWE1-deficient B cells exhibited increased Myc target gene expression despite reduced proliferation.

Conclusions:

• HUWE1 is essential for coordinating the transition of naive B cells to antigen-activated cells.
• HUWE1 regulates mutagenic processes in B cells by controlling AID expression and post-transcriptional output of Myc target genes.
• These findings highlight HUWE1 as a key regulator in B-cell adaptive immune responses.