Reduced immunoglobulin class switch recombination in the absence of Artemis.
Nonhomologous end-joining DNA repair factors, including Artemis, are all required for the repair of DNA double-strand breaks, which occur during the assembly of the variable antigen recognition domain of B-cell receptors and T-cell receptors through the V(D)J recombination. Mature B cells further shape their immunoglobulin repertoire on antigen recognition notably through the class switch recombination (CSR) process. To analyze the role of Artemis during CSR, we developed a mature B-cell-specific Artemis conditional knockout mouse to bypass the absence of B cells caused by its early deficit. Although CSR is not overwhelmingly affected in these mice, class switching to certain isotypes is clearly reduced both in vitro on B-cell activation and in vivo after keyhole limpet hemocyanin immunization. The reduced CSR in Artemis-deficient B cells is accompanied by the increase in DNA microhomology usage at CSR junctions, the imprint of an alternative DNA end-joining pathway. Likewise, significant increase in DNA microhomology usage is the signature of CSR junctions obtained from human RS-SCID patients harboring hypomorphic Artemis mutations. Altogether, this indicates that Artemis participates in the repair of a subset of DNA breaks generated during CSR.
Rivera-Munoz
Paola
P
Inserm U768, Paris, France.
Soulas-Sprauel
Pauline
P
Le Guyader
Gwenaël
G
Abramowski
Vincent
V
Bruneau
Sylvia
S
Fischer
Alain
A
Pâques
Frédéric
F
de Villartay
Jean-Pierre
JP
D000328:Adult; D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism; D001483:Base Sequence; D015153:Blotting, Western; D002648:Child; D053903:DNA Breaks, Double-Stranded; D004720:Endonucleases; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006433:Hemocyanins / Q000008:administration & dosage; D006801:Humans; D007070:Immunoglobulin A / Q000235:genetics*; D017578:Immunoglobulin Class Switching / Q000235:genetics*; D007074:Immunoglobulin G / Q000235:genetics*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011995:Recombination, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D016511:Severe Combined Immunodeficiency / Q000235:genetics*
D007070:Immunoglobulin A; D007074:Immunoglobulin G; D009687:Nuclear Proteins; D012333:RNA, Messenger; D006433:Hemocyanins; D004720:Endonucleases; C473337:Dclre1c protein, mouse; C032808:keyhole-limpet hemocyanin