Kitamura D and Rajewsky K:
Targeted disruption of mu-chain membrane exon causes loss of heavy-chain allelic exclusion.
Nature 1992 Mar 12;356:154-156

ABSTRACT
Burnet's clonal selection theory suggests that each B lymphocyte is committed to a single antibody specificity. This is achieved by a programme of somatic rearrangements of the gene segments encoding antibody variable (V) regions, in the course of B-cell development. Evidence from immunoglobulin-transgenic mice and transformed pre-B cells suggests that the membrane form of the immunoglobulin heavy (H) chain of class mu (mu m), expressed from a rearranged H-chain (IgH) locus, may signal allelic exclusion of the homologous IgH locus in the cell and initiation of light (L) chain gene rearrangment in the Ig kappa loci. We report here that targeted disruption of the membrane exon of the mu chain indeed results in the loss of H-chain allelic exclusion. But, some kappa chain gene rearrangment is still observed in the absence of mu m expression.

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