RAG-mediated DNA double-strand breaks activate a cell type-specific checkpoint to inhibit pre-B cell receptor signals

• Published in: The Journal of experimental medicine 2016-02, Vol.213 (2), p.209-223
• Main Authors: Bednarski, Jeffrey J, Pandey, Ruchi, Schulte, Emily, White, Lynn S, Chen, Bo-Ruei, Sandoval, Gabriel J, Kohyama, Masako, Haldar, Malay, Nickless, Andrew, Trott, Amanda, Cheng, Genhong, Murphy, Kenneth M, Bassing, Craig H, Payton, Jacqueline E, Sleckman, Barry P
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing - metabolism; Animals; Ataxia Telangiectasia Mutated Proteins - deficiency; Ataxia Telangiectasia Mutated Proteins - genetics; Ataxia Telangiectasia Mutated Proteins - metabolism; Cell Cycle Checkpoints - immunology; Cell Proliferation; DNA Breaks, Double-Stranded; DNA-Binding Proteins - deficiency; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Gene Rearrangement, B-Lymphocyte, Light Chain; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; Intracellular Signaling Peptides and Proteins - metabolism; Mice; Mice, Knockout; Mice, Transgenic; NF-kappa B p52 Subunit - deficiency; NF-kappa B p52 Subunit - genetics; NF-kappa B p52 Subunit - metabolism; NF-kappaB-Inducing Kinase; Pre-B Cell Receptors - metabolism; Precursor Cells, B-Lymphoid - cytology; Precursor Cells, B-Lymphoid - immunology; Precursor Cells, B-Lymphoid - metabolism; Protein Serine-Threonine Kinases - metabolism; Protein-Tyrosine Kinases - metabolism; Proto-Oncogene Proteins - metabolism; Signal Transduction - immunology; Syk Kinase; Trans-Activators - metabolism
• ISSN: 0022-1007; 1540-9538
• DOI: 10.1084/jem.20151048

DNA double-strand breaks (DSBs) activate a canonical DNA damage response, including highly conserved cell cycle checkpoint pathways that prevent cells with DSBs from progressing through the cell cycle. In developing B cells, pre-B cell receptor (pre-BCR) signals initiate immunoglobulin light (Igl) chain gene assembly, leading to RAG-mediated DNA DSBs. The pre-BCR also promotes cell cycle entry, which could cause aberrant DSB repair and genome instability in pre-B cells. Here, we show that RAG DSBs inhibit pre-BCR signals through the ATM- and NF-κB2-dependent induction of SPIC, a hematopoietic-specific transcriptional repressor. SPIC inhibits expression of the SYK tyrosine kinase and BLNK adaptor, resulting in suppression of pre-BCR signaling. This regulatory circuit prevents the pre-BCR from inducing additional Igl chain gene rearrangements and driving pre-B cells with RAG DSBs into cycle. We propose that pre-B cells toggle between pre-BCR signals and a RAG DSB-dependent checkpoint to maintain genome stability while iteratively assembling Igl chain genes.