title: The cytoplasmic domains of immunoglobulin (Ig) alpha and Ig beta can independently induce the precursor B cell transition and allelic exclusion.
abstract: In mature B cells, signals transduced through membrane immunoglobulin (Ig) produce cellular activation, yet the same receptor can also mediate deletion and silencing of autoreactive B cells. In addition, Ig expression during the antigen-independent phase of B cell development regulates the precursor B (pre-B) cell transition and allelic exclusion. To account for the diverse regulatory functions induced by membrane Ig, it has been proposed that individual receptor components have independent physiologic activities. Here we establish a role for Ig alpha in the pre-B cell transition and allelic exclusion. We find that the cytoplasmic domain of Ig alpha contains sufficient information to trigger both of these antigen-independent events. Direct comparisons of the cytoplasmic domains of Ig alpha and Ig beta show that the two are indistinguishable in the induction of the pre-B cell transition and allelic exclusion. Our experiments suggest that, despite the reported differences in certain biochemical assays, Ig alpha and Ig beta have redundant functions in the developing B cell.
authors.affiliation: Laboratory of Molecular Immunology, Rockefeller University, New York, USA.
authors.forename: F
authors.initials: F
authors.lastname: Papavasiliou
authors.forename: M
authors.initials: M
authors.lastname: Jankovic
authors.forename: H
authors.initials: H
authors.lastname: Suh
authors.forename: M C
authors.initials: MC
authors.lastname: Nussenzweig
mesh_terms: D000483:Alleles; D000818:Animals; D015703:Antigens, CD / Q000737:chemistry / Q000502:physiology*; D001402:B-Lymphocytes / Q000166:cytology*; D051925:CD79 Antigens; D002454:Cell Differentiation; D017637:Clonal Deletion; D005803:Genes, Immunoglobulin; D006183:H-2 Antigens / Q000276:immunology; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D007143:Immunoglobulin Heavy Chains / Q000502:physiology*; D007147:Immunoglobulin Light Chains / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic; D010446:Peptide Fragments / Q000494:pharmacology*; D017434:Protein Structure, Tertiary; D011947:Receptors, Antigen, B-Cell / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000502:physiology; D017634:Self Tolerance; D015398:Signal Transduction; D019076:Transgenes; D018909:src Homology Domains / Q000502:physiology*
chemical_list: D015703:Antigens, CD; D051925:CD79 Antigens; C497882:Cd79a protein, mouse; C497884:Cd79b protein, mouse; D006183:H-2 Antigens; C024755:H-2K(K) antigen; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D010446:Peptide Fragments; D011947:Receptors, Antigen, B-Cell; D011993:Recombinant Fusion Proteins