The zebrafish IgH locus contains multiple transcriptional regulatory regions

Dev Comp Immunol. 2011 Mar;35(3):352-9. doi: 10.1016/j.dci.2010.10.010. Epub 2010 Nov 11.


Many fish have, in addition to IgM and IgD, a third isotype called IgZ or IgT. The ζ-chain locus is embedded among the Ig heavy chain V-, D- and J-elements in a manner reminiscent of the TcR δ/α locus. Isotype selection thus occurs during VDJ recombination, a process that is facilitated by intralocus transcription. Using in silico analyses and enhancer reporter vectors we identified 3 new regions within the zebrafish IgH locus through which transcription can be activated in catfish B-cell lines. Two of these, termed Eζi (Jζ to Cζ1 intronic) and Eζ3' regions flank the ζ-chain constant domain exons. A third region, Eδ3', resides downstream of the δ-chain exons. All regions contain predicted binding sites for transcription factors that contribute to B-cell specific transcription in fish and mammals. Each region also has proximal matrix attachment regions, which may further contribute to transcriptional activation and chromatin remodeling. We discuss possible roles for these regions during VDJ recombination.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • B-Lymphocytes / immunology
  • Base Sequence
  • Cell Line
  • Fish Proteins / genetics*
  • Gene Expression Regulation / genetics*
  • Gene Expression Regulation / immunology
  • Genes, Immunoglobulin Heavy Chain / genetics*
  • Genetic Loci
  • Molecular Sequence Data
  • Regulatory Elements, Transcriptional / genetics*
  • Sequence Alignment
  • Zebrafish / genetics*
  • Zebrafish / immunology


  • Fish Proteins