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Dependence of antibody gene diversification on uracil excision
Activation-induced deaminase (AID) catalyses deamination of deoxycytidine to deoxyuridine within immunoglobulin loci, triggering pathways of antibody diversification that are largely dependent on uracil-DNA glycosylase (uracil-N-glycolase [UNG]). Surprisingly efficient class switch recombination is...
Autores principales: | , , , , , |
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Formato: | Texto |
Lenguaje: | English |
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The Rockefeller University Press
2007
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2150978/ https://www.ncbi.nlm.nih.gov/pubmed/18070939 http://dx.doi.org/10.1084/jem.20071768 |
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author | Di Noia, Javier M. Williams, Gareth T. Chan, Denice T.Y. Buerstedde, Jean-Marie Baldwin, Geoff S. Neuberger, Michael S. |
author_facet | Di Noia, Javier M. Williams, Gareth T. Chan, Denice T.Y. Buerstedde, Jean-Marie Baldwin, Geoff S. Neuberger, Michael S. |
author_sort | Di Noia, Javier M. |
collection | PubMed |
description | Activation-induced deaminase (AID) catalyses deamination of deoxycytidine to deoxyuridine within immunoglobulin loci, triggering pathways of antibody diversification that are largely dependent on uracil-DNA glycosylase (uracil-N-glycolase [UNG]). Surprisingly efficient class switch recombination is restored to ung(−/−) B cells through retroviral delivery of active-site mutants of UNG, stimulating discussion about the need for UNG's uracil-excision activity. In this study, however, we find that even with the overexpression achieved through retroviral delivery, switching is only mediated by UNG mutants that retain detectable excision activity, with this switching being especially dependent on MSH2. In contrast to their potentiation of switching, low-activity UNGs are relatively ineffective in restoring transversion mutations at C:G pairs during hypermutation, or in restoring gene conversion in stably transfected DT40 cells. The results indicate that UNG does, indeed, act through uracil excision, but suggest that, in the presence of MSH2, efficient switch recombination requires base excision at only a small proportion of the AID-generated uracils in the S region. Interestingly, enforced expression of thymine-DNA glycosylase (which can excise U from U:G mispairs) does not (unlike enforced UNG or SMUG1 expression) potentiate efficient switching, which is consistent with a need either for specific recruitment of the uracil-excision enzyme or for it to be active on single-stranded DNA. |
format | Text |
id | pubmed-2150978 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2007 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21509782008-06-24 Dependence of antibody gene diversification on uracil excision Di Noia, Javier M. Williams, Gareth T. Chan, Denice T.Y. Buerstedde, Jean-Marie Baldwin, Geoff S. Neuberger, Michael S. J Exp Med Articles Activation-induced deaminase (AID) catalyses deamination of deoxycytidine to deoxyuridine within immunoglobulin loci, triggering pathways of antibody diversification that are largely dependent on uracil-DNA glycosylase (uracil-N-glycolase [UNG]). Surprisingly efficient class switch recombination is restored to ung(−/−) B cells through retroviral delivery of active-site mutants of UNG, stimulating discussion about the need for UNG's uracil-excision activity. In this study, however, we find that even with the overexpression achieved through retroviral delivery, switching is only mediated by UNG mutants that retain detectable excision activity, with this switching being especially dependent on MSH2. In contrast to their potentiation of switching, low-activity UNGs are relatively ineffective in restoring transversion mutations at C:G pairs during hypermutation, or in restoring gene conversion in stably transfected DT40 cells. The results indicate that UNG does, indeed, act through uracil excision, but suggest that, in the presence of MSH2, efficient switch recombination requires base excision at only a small proportion of the AID-generated uracils in the S region. Interestingly, enforced expression of thymine-DNA glycosylase (which can excise U from U:G mispairs) does not (unlike enforced UNG or SMUG1 expression) potentiate efficient switching, which is consistent with a need either for specific recruitment of the uracil-excision enzyme or for it to be active on single-stranded DNA. The Rockefeller University Press 2007-12-24 /pmc/articles/PMC2150978/ /pubmed/18070939 http://dx.doi.org/10.1084/jem.20071768 Text en Copyright © 2007, The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/). |
spellingShingle | Articles Di Noia, Javier M. Williams, Gareth T. Chan, Denice T.Y. Buerstedde, Jean-Marie Baldwin, Geoff S. Neuberger, Michael S. Dependence of antibody gene diversification on uracil excision |
title | Dependence of antibody gene diversification on uracil excision |
title_full | Dependence of antibody gene diversification on uracil excision |
title_fullStr | Dependence of antibody gene diversification on uracil excision |
title_full_unstemmed | Dependence of antibody gene diversification on uracil excision |
title_short | Dependence of antibody gene diversification on uracil excision |
title_sort | dependence of antibody gene diversification on uracil excision |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2150978/ https://www.ncbi.nlm.nih.gov/pubmed/18070939 http://dx.doi.org/10.1084/jem.20071768 |
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