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Altering the pathway of immunoglobulin hypermutation by inhibiting uracil-DNA glycosylase


A functional immune system depends on the production of a wide range of immunoglobulin molecules. Immunoglobulin variable region (IgV) genes are diversified after gene rearrangement by hypermutation. In the DNA deamination model, we have proposed that deamination of dC residues to dU by activation-induced deaminase (AID) triggers this diversification. In hypermutating chicken DT40 B cells, most IgV mutations are dC → dG/dA or dG → dC/dT transversions, which are proposed to result from replication over sites of base loss produced by the excision activity of uracil-DNA glycosylase. Blocking the activity of uracil-DNA glycosylase should instead lead to replication over the dU lesion, resulting in dC → dT (and dG → dA) transitions. Here we show that expression in DT40 cells of a bacteriophage-encoded protein that inhibits uracil-DNA glycosylase shifts the pattern of IgV gene mutations from transversion dominance to transition dominance. This is good evidence that antibody diversification involves dC → dU deamination within the immunoglobulin locus itself.

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Figure 1: Uracil-DNA glycosylase activity in the DT40 B-cell line.
Figure 2: Analysis of Vλ mutations in surface IgM-loss variants sorted from pEF-Ugi and control transfectants.
Figure 3: Analysis of Vλ mutations in unsorted populations of pEF-Ugi and control transfectants after 3–8 weeks of clonal expansion.


  1. Petersen-Mahrt, S. K., Harris, R. S. & Neuberger, M. S. AID mutates E. coli suggesting a DNA deamination mechanism for antibody diversification. Nature 418, 99–103 (2002)

    ADS  CAS  Article  Google Scholar 

  2. Muramatsu, M. et al. Specific expression of activation-induced cytidine deaminase (AID), a novel member of the RNA-editing deaminase family in germinal center B cells. J. Biol. Chem. 274, 18470–18476 (1999)

    CAS  Article  Google Scholar 

  3. Lindahl, T. Suppression of spontaneous mutagenesis in human cells by DNA base excision-repair. Mutat. Res. 462, 129–135 (2000)

    CAS  Article  Google Scholar 

  4. Lindahl, T. An N-glycosidase from Escherichia coli that releases free uracil from DNA containing deaminated cytosine residues. Proc. Natl Acad. Sci. USA 71, 3649–3653 (1974)

    ADS  CAS  Article  Google Scholar 

  5. Takata, M. et al. Chromosome instability and defective recombinational repair in knockout mutants of the five Rad51 paralogs. Mol. Cell. Biol. 21, 2858–2866 (2001)

    CAS  Article  Google Scholar 

  6. Sale, J. E., Calandrini, D. M., Takata, M., Takeda, S. & Neuberger, M. S. Ablation of XRCC2/3 transforms immunoglobulin V gene conversion into somatic hypermutation. Nature 412, 921–926 (2001)

    ADS  CAS  Article  Google Scholar 

  7. Lindahl, T. Instability and decay of the primary structure of DNA. Nature 362, 709–715 (1993)

    ADS  CAS  Article  Google Scholar 

  8. Pearl, L. H. Structure and function in the uracil-DNA glycosylase superfamily. Mutat. Res. 460, 165–181 (2000)

    ADS  CAS  Article  Google Scholar 

  9. Nilsen, H. et al. Uracil-DNA glycosylase (UNG)-deficient mice reveal a primary role of the enzyme during DNA replication. Mol. Cell 5, 1059–1065 (2000)

    CAS  Article  Google Scholar 

  10. Haushalter, K. A., Todd Stukenberg, M. W., Kirschner, M. W. & Verdine, G. L. Identification of a new uracil-DNA glycosylase family by expression cloning using synthetic inhibitors. Curr. Biol. 9, 174–185 (1999)

    CAS  Article  Google Scholar 

  11. Nilsen, H. et al. Excision of deaminated cytosine from the vertebrate genome: role of the SMUG1 uracil-DNA glycosylase. EMBO J. 20, 4278–4286 (2001)

    CAS  Article  Google Scholar 

  12. Friedberg, E. C., Ganesan, A. K. & Minton, K. N-glycosidase activity in extracts of Bacillus subtilis and its inhibition after infection with bacteriophage PBS2. J. Virol. 16, 315–321 (1975)

    CAS  PubMed  Google Scholar 

  13. Wang, Z. & Mosbaugh, D. W. Uracil-DNA glycosylase inhibitor of bacteriophage PBS2: cloning and effects of expression of the inhibitor gene in Escherichia coli. J. Bacteriol. 170, 1082–1091 (1988)

    CAS  Article  Google Scholar 

  14. Karran, P., Cone, R. & Friedberg, E. C. Specificity of the bacteriophage PBS2 induced inhibitor of uracil-DNA glycosylase. Biochemistry 20, 6092–6096 (1981)

    CAS  Article  Google Scholar 

  15. Mol, C. D. et al. Crystal structure of human uracil-DNA glycosylase in complex with a protein inhibitor: protein mimicry of DNA. Cell 82, 701–708 (1995)

    CAS  Article  Google Scholar 

  16. Handa, P., Roy, S. & Varshney, U. The role of leucine 191 of Escherichia coli uracil DNA glycosylase in the formation of a highly stable complex with the substrate mimic, Ugi, and in uracil excision from the synthetic substrates. J. Biol. Chem. 276, 17324–17331 (2001)

    CAS  Article  Google Scholar 

  17. Radany, E. H. et al. Increased spontaneous mutation frequency in human cells expressing the phage PBS2-encoded inhibitor of uracil-DNA glycosylase. Mutat. Res. 461, 41–58 (2000)

    CAS  Article  Google Scholar 

  18. Harris, R. S., Sale, J. E., Petersen-Mahrt, S. K. & Neuberger, M. S. AID is essential for immunoglobulin V gene conversion in a cultured B cell line. Curr. Biol. 12, 435–438 (2002)

    CAS  Article  Google Scholar 

  19. Baba, T. W., Giroir, B. P. & Humphries, E. H. Cell lines derived from avian lymphomas exhibit two distinct phenotypes. Virology 144, 139–151 (1985)

    CAS  Article  Google Scholar 

  20. Buerstedde, J. M. et al. Light chain gene conversion continues at high rate in an ALV-induced cell line. EMBO J. 9, 921–927 (1990)

    CAS  Article  Google Scholar 

  21. Harris, R. S., Croom-Carter, D. S., Rickinson, A. B. & Neuberger, M. S. Epstein–Barr virus and the somatic hypermutation of immunoglobulin genes in Burkitt's lymphoma cells. J. Virol. 75, 10488–10492 (2001)

    CAS  Article  Google Scholar 

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We thank R. Savva for the Ugi cassette, S. Takeda for XRCC2-deficient DT40 cells, R. Grenfell for help with cell sorting, and R. Harris, S. Petersen-Mahrt, C. Rada and J. Sale for discussions. J.D.N. was supported by a César Milstein fellowship and the Fundación Antorchas, Argentina.

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Correspondence to Michael S. Neuberger.

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Di Noia, J., Neuberger, M. Altering the pathway of immunoglobulin hypermutation by inhibiting uracil-DNA glycosylase. Nature 419, 43–48 (2002).

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