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  • The EMBO Journal (2007) 26, 4273 - 4282
  • doi:10.1038/sj.emboj.7601846

Published online: 6 September 2007

Transcription of productive and nonproductive VDJ-recombined alleles after IgH allelic exclusion

Janssen Daly1,a, Steve Licence1, Aikaterini Nanou2, Geoff Morgan3 and Inga-Lill Mårtensson1

  1. Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge, UK
  2. Chromatin and Gene expression, The Babraham Institute, Cambridge, UK
  3. Flow Cytometry Facility, The Babraham Institute, Cambridge, UK

Correspondence to:

Inga-Lill Mårtensson, Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, The Babraham Research Campus, Cambridge CB2 4AT, UK. Tel.: +44 1223 496469; Fax: +44 1223 496023; E-mail: lill.martensson@bbsrc.ac.uk

aPresent address: Laboratory of Molecular Genetics, NIEHS, Durham, NC, USA

Received 21 March 2007; Accepted 8 August 2007

The process of allelic exclusion ensures that each B cell expresses a B-cell receptor encoded by only one of its Ig heavy (IgH) and light (IgL) chain alleles. Although its precise mechanism is unknown, recruitment of the nonfunctional IgH allele to centromeric heterochromatin correlates with the establishment of allelic exclusion. Similarly, recruitment in activated splenic B cells correlates with cell division. In the latter, the recruited IgH allele was reported to be transcriptionally silent. However, it is not known whether monoallelic recruitment during establishment of allelic exclusion correlates with transcriptional silencing. To investigate this, we assessed the transcriptional status of both IgH alleles in single primary cells over the course of B-cell development, using RNA fluorescence in situ hybridization. Before allelic exclusion both alleles are transcribed. Thereafter, in pre-BII and subsequent developmental stages both functional and nonfunctional VDJ- and DJ-transcription is observed. Thus, after the establishment of IgH allelic exclusion, monoallelic recruitment to heterochromatin does not silence VDJ- or DJ-transcription, but serves another purpose.

  • Keywords:

    • allelic exclusion,
    • B-cell development,
    • heterochromatin,
    • IgH transcription