Immunoglobulin beta signaling regulates locus accessibility for ordered immunoglobulin gene rearrangements.
The antigen receptor gene rearrangement at a given locus is tightly regulated with respect to cell lineage and developmental stage by an ill-defined mechanism. To study the possible role of precursor B cell antigen receptor (pre-BCR) signaling in the regulation of the ordered immunoglobulin (Ig) gene rearrangement during B cell differentiation, a newly developed system using mu heavy (H) chain membrane exon (microm)-deficient mice was employed. In this system, the antibody-mediated cross-linking of Igbeta on developmentally arrested progenitor B (pro-B) cells mimicked pre-BCR signaling to induce early B cell differentiation in vivo. Analyses with ligation-mediated polymerase chain reaction revealed that the Igbeta cross-linking induced the redirection of Ig gene rearrangements, namely, the suppression of ongoing rearrangements at the H chain locus and the activation of rearrangements at the light (L) chain locus. Upon the cross-linking, the kappaL chain germline transcription was found to be upregulated whereas the V(H) germline transcription was promptly downregulated. Notably, this alteration of the accessibility at the H and L chain loci was detected even before the induction of cellular differentiation became detectable by the change of surface phenotype. Thus, the pre-BCR signaling through Igbeta appears to regulate the ordered Ig gene rearrangement by altering the Ig locus accessibility.
Maki
K
K
Department of Immunology, Tokyo Metropolitan Organization for Medical Research, The Tokyo Metropolitan Institute of Medical Science, Tokyo 113-8613, Japan.
Nagata
K
K
Kitamura
F
F
Takemori
T
T
Karasuyama
H
H
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D001483:Base Sequence; D002454:Cell Differentiation; D003432:Cross-Linking Reagents / Q000494:pharmacology; D017931:DNA Primers / Q000235:genetics; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D011947:Receptors, Antigen, B-Cell / Q000235:genetics*; D015398:Signal Transduction
D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D003432:Cross-Linking Reagents; D017931:DNA Primers; D011947:Receptors, Antigen, B-Cell