Contribution of Vh gene replacement to the primary B cell repertoire.
V(H) replacement has been proposed as one way to modify unwanted antibody specificities, but analysis of this mechanism has been limited without a dynamic cellular model. We describe a human cell line that spontaneously undergoes serial V(H) gene replacement mediated by cryptic recombination signal sequences (cRSS) located near the 3' end of V(H) genes. Recombination-activating gene products, RAG-1 and RAG-2, bind and cleave the cRSS to generate DNA deletion circles during the V(H) replacement process. A V(H) replacement contribution to normal repertoire development is revealed by the identification of V(H) replacement "footprints" in IgH sequences and double-stranded DNA breaks at V(H) cRSS sites in immature B cells. Surprisingly, the residual 3' sequences of replaced V(H) genes contribute charged amino acids to the CDR3 region, a hallmark of autoreactive antibodies.
Zhang
Zhixin
Z
Division of Developmental and Clinical Immunology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
Zemlin
Michael
M
Wang
Yui-Hsi
YH
Munfus
Delicia
D
Huye
Leslie E
LE
Findley
Harry W
HW
Bridges
S Louis
SL
Roth
David B
DB
Burrows
Peter D
PD
Cooper
Max D
MD
D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D002478:Cells, Cultured; D022801:Complementarity Determining Regions; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000502:physiology; D005803:Genes, Immunoglobulin; D018398:Homeodomain Proteins / Q000502:physiology; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic
D022801:Complementarity Determining Regions; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D009687:Nuclear Proteins; C499311:RAG2 protein, human; C064655:V(D)J recombination activating protein 2; C064658:RAG-1 protein