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Immunoglobulin Class Switch Recombination

Immunoglobulin Class Switch Recombination A B lymphocyte that produces the immunoglobulin heavy (H) chain J1 may switch to the production of another heavy chain class: y, E, or IY.. Since the new heavy chain retains the original variable (V) region, antigenic specificity is maintained. The switch is accompanied by a large deletion of DNA at the heavy chain locus. To explain how this deletion is generated, three models have been proposed: recombination between homologs, unequal sister chromatid exchange, and looping out and deletion. While none of the predicted recombination products of the first two models have been found, both by-products of looping out-inversions and circular DNA-have been isolated. Thus looping out and deletion appears to be the appropriate model to explain the genetic events leading to the immunoglobulin heavy chain class switch. One requirement for switching may be transcription of the constant (C) region to which the cell switches. The switch rearrangement is catalyzed by a switch recombinase, and the isolation of the components of this putative enzyme system is in progress. Although the switch deletion is an accepted fact, the discussion is enlivened by scenarios for switching without DNA rearrangement; such suggestions include processing at the RNA level and trans-splicing. INTRODUCTION http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Annual Review of Immunology Annual Reviews

Immunoglobulin Class Switch Recombination

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References (57)

Publisher
Annual Reviews
Copyright
Copyright 1993 Annual Reviews. All rights reserved
Subject
Review Articles
ISSN
0732-0582
eISSN
1545-3278
DOI
10.1146/annurev.iy.11.040193.002045
pmid
8476566
Publisher site
See Article on Publisher Site

Abstract

A B lymphocyte that produces the immunoglobulin heavy (H) chain J1 may switch to the production of another heavy chain class: y, E, or IY.. Since the new heavy chain retains the original variable (V) region, antigenic specificity is maintained. The switch is accompanied by a large deletion of DNA at the heavy chain locus. To explain how this deletion is generated, three models have been proposed: recombination between homologs, unequal sister chromatid exchange, and looping out and deletion. While none of the predicted recombination products of the first two models have been found, both by-products of looping out-inversions and circular DNA-have been isolated. Thus looping out and deletion appears to be the appropriate model to explain the genetic events leading to the immunoglobulin heavy chain class switch. One requirement for switching may be transcription of the constant (C) region to which the cell switches. The switch rearrangement is catalyzed by a switch recombinase, and the isolation of the components of this putative enzyme system is in progress. Although the switch deletion is an accepted fact, the discussion is enlivened by scenarios for switching without DNA rearrangement; such suggestions include processing at the RNA level and trans-splicing. INTRODUCTION

Journal

Annual Review of Immunology – Annual Reviews

Published: Apr 1, 1993

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