The cleavage efficiency of the human immunoglobulin heavy chain VH elements by the RAG complex: implications for the immune repertoire.
The human immunoglobulin heavy chain locus contains 39 functional human V(H) elements. All 39 V(H) elements (with their adjacent heptamer/nonamer signal) were tested for site-specific cleavage with purified human core RAG1 and RAG2, and HMG1 proteins in a 12/23-coupled cleavage reaction. Both nicking and hairpin formation were measured. The individual V(H) cleavage efficiencies vary over nearly a 30-fold range. These measurements will be useful in considering the factors affecting the generation of the immunoglobulin and T-cell receptor repertoires in the adult humans. Interestingly, when these cleavage efficiencies are summed for each of the V(H) families, the six V(H) family efficiencies correspond closely to the observed profile of unselected V(H) family usage in the peripheral B cells of normal adult humans. This correspondence raises the possibility that the dominant factor determining V(H) element utilization within the 1-megabase human genomic V(H) array is simply the individual RAG cleavage efficiencies.
Yu
Kefei
K
Norris Comprehensive Cancer Center, Department of Pathology, , University of Southern California, Keck School of Medicine, Los Angeles, California 90089-9176, USA.
Taghva
Alex
A
Lieber
Michael R
MR
D000328:Adult; D001402:B-Lymphocytes / Q000378:metabolism; D001483:Base Sequence; D001667:Binding, Competitive; D002843:Chromatin / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005982:Glutathione Transferase / Q000378:metabolism; D024243:HMGB1 Protein / Q000737:chemistry / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011995:Recombination, Genetic; D013997:Time Factors
D002843:Chromatin; D004268:DNA-Binding Proteins; D024243:HMGB1 Protein; D018398:Homeodomain Proteins; D007143:Immunoglobulin Heavy Chains; D009687:Nuclear Proteins; C499311:RAG2 protein, human; C064655:V(D)J recombination activating protein 2; C064658:RAG-1 protein; D005982:Glutathione Transferase