The ESC: The Dangerous By-Product of V(D)J Recombination.

Smith AL., Scott JNF., Boyes J.

V(D)J recombination generates antigen receptor diversity by mixing and matching individual variable (V), diversity (D), and joining (J) gene segments. An obligate by-product of many of these reactions is the excised signal circle (ESC), generated by excision of the DNA from between the gene segments. Initially, the ESC was believed to be inert and formed to protect the genome from reactive broken DNA ends but more recent work suggests that the ESC poses a substantial threat to genome stability. Crucially, the recombinase re-binds to the ESC, which can result in it being re-integrated back into the genome, to cause potentially oncogenic insertion events. In addition, very recently, the ESC/recombinase complex was found to catalyze breaks at recombination signal sequences (RSSs) throughout the genome, via a "cut-and-run" mechanism. Remarkably, the ESC/recombinase complex triggers these breaks at key leukemia driver genes, implying that this reaction could be a significant cause of lymphocyte genome instability. Here, we explore these alternate pathways and discuss their relative dangers to lymphocyte genome stability.

DOI

10.3389/fimmu.2019.01572

Type

Journal article

Journal

Front Immunol

Publication Date

2019

Volume

10

Keywords

RAG proteins, V(D)J recombination, double strand breaks, genome instability, leukemia, Animals, Genome, Human, Genomic Instability, Humans, Leukemia, V(D)J Recombination

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