To examine the role of light chains in early B cell development we combined RAG-1 and lambda 5 mutations to produce mice that expressed neither conventional nor surrogate light chains (RAG-1-/-, lambda 5-/-). Unique heavy and light chain genes were then introduced into the double and single mutant backgrounds. Membrane immunoglobulin (Ig)mu (mIg mu) associated with Ig alpha-Ig beta but was unable to activate the pre-B cell transition in RAG-1-/-lambda 5-/- mice. Either lambda 5 or kappa light chains were sufficient to complement this deficiency. Therefore light chains are absolutely required for a functional Ig signaling module in early B cell development. Our data provide direct evidence for the existence of two pathways for induction of early B cell development: one which is activated through surrogate light chains and mIg mu, and an alternative pathway which uses conventional light chains and mIg mu.
Surrogate or conventional light chains are required for membrane immunoglobulin mu to activate the precursor B cell transition.
F Papavasiliou, M Jankovic, M C Nussenzweig; Surrogate or conventional light chains are required for membrane immunoglobulin mu to activate the precursor B cell transition.. J Exp Med 1 November 1996; 184 (5): 2025–2030. doi: https://doi.org/10.1084/jem.184.5.2025
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