Full length RAG2 expression enhances the DNA damage response in pre-B cells

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• V(D)J recombination in lymphocytes involves DNA double-strand breaks (DSBs) mediated by RAG1/RAG2.
• RAG2 protein is known to translocate to the centrosome following DSB induction, suggesting a role in DNA damage response.

Purpose of the Study:

• To investigate the impact of full-length (FL) wild-type RAG2 versus a nuclear export-defective T490A mutant on pre-B cell viability and cell cycle progression after DSB generation.

Main Methods:

• Pre-B cells expressing GFP-labeled FL RAG2 or T490A RAG2 mutant were subjected to irradiation to induce DSBs.
• Cell apoptosis, Caspase 3 cleavage, phospho-p53 levels, and cell division/mitosis rates were measured.

Main Results:

• FL RAG2-expressing cells showed increased apoptosis and Caspase 3 cleavage compared to the T490A mutant post-irradiation.
• Both RAG2 variants induced similar phospho-p53 increases.
• FL RAG2 cells exhibited enhanced cell division and mitosis rates, indicating improved recovery after initial apoptosis.

Conclusions:

• Full-length RAG2, unlike its nuclear export-defective mutant, plays a role in pre-B cell fate determination between apoptosis and DNA repair/cell cycle progression following DNA damage.
• RAG2's subcellular localization influences cellular responses to genotoxic stress during lymphocyte development.