Immunoglobulin heavy and light chain genes rearrange independently at early stages of B cell development

Abstract

The compartment of mouse B cell progenitors can be resolved into five developmentally related fractions by multicolor flow cytometry. Using this system and employing mutant mice in which the membrane exon of the μ chain, the λ5 gene, or the J H locus was inactivated by gene targeting, we found that expression of the pre-B cell receptor complex is necessary for the transition from the large CD43 + to the small CD43 − pre-B cell stage. We report the occurrence of immunoglobulin heavy and light chain gene rearrangement at the stage of large B cell precursors. We show that neither the pre-B cell receptor complex nor any gene rearrangement in the heavy chain locus is required for the induction of κ light chain gene rearrangement in early B cell progenitors.