Reciprocal homologous recombination in or near antibody VDJ genes

Asad Umar, Patricia J. Gearhart

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


To determine if rearranged heavy chain variable (VDJ) genes can recombine with each other by crossing over of DNA strands, we constructed a transgene that contained a promoter, VDJ gene, reporter gene to detect crossover events, intron enhancer, matrix attachment region, and constant gene for IgM (Cμ). Following immunization of transgenic mice, hybrid molecules were isolated from B cell DNA which contained the transgene recombined with the endogenous IgH locus. Reciprocal products of crossovers were detected by plasmid rescue and PCR amplification, and they were sequenced. Recombination occurred somewhere within 147 bp of homology that contained the JH4 gene segment and 3′ flanking DNA. The recombined transgenes had a 20‐fold increase in mutation in the VDJ region compared to nonrecombined transgenes, which indicates that DNA sequences 3′ of the Cμ gene in the endogenous IgH locus are necessary for full activity of the mutator mechanism. The recovery of recombinants between VDJ transgenes and endogenous VDJ genes raises the possibility that reciprocal recombination may somatically diversify rearranged genes between maternal and paternal alleles.

Original languageEnglish (US)
Pages (from-to)2392-2400
Number of pages9
JournalEuropean Journal of Immunology
Issue number8
StatePublished - Aug 1995
Externally publishedYes


  • Homologous recombination
  • IgH locus
  • Immunoglobulin transgenes
  • Somatic mutation

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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