title: A role for interferon regulatory factor 4 in receptor editing.
abstract: Receptor editing is the primary means through which B cells revise antigen receptors and maintain central tolerance. Previous studies have demonstrated that interferon regulatory factor 4 (IRF-4) and IRF-8 promote immunoglobulin light-chain rearrangement and transcription at the pre-B stage. Here, the roles of IRF-4 and -8 in receptor editing were analyzed. Our results show that secondary rearrangement was impaired in IRF-4 but not IRF-8 mutant mice, suggesting that receptor editing is defective in the absence of IRF-4. The role of IRF-4 in receptor editing was further examined in B-cell-receptor (BCR) transgenic mice. Our results show that secondary rearrangement triggered by membrane-bound antigen was defective in the IRF-4-deficient mice. Our results further reveal that the defect in secondary rearrangement is more severe at the immunoglobulin lambda locus than at the kappa locus, indicating that IRF-4 is more critical for the lambda rearrangement. We provide evidence demonstrating that the expression of IRF-4 in immature B cells is rapidly induced by self-antigen and that the reconstitution of IRF-4 expression in the IRF-4 mutant immature B cells promotes secondary rearrangement. Thus, our studies identify IRF-4 as a nuclear effector of a BCR signaling pathway that promotes secondary rearrangement at the immature B-cell stage.
authors.affiliation: Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA.
authors.forename: Simanta
authors.initials: S
authors.lastname: Pathak
authors.forename: Shibin
authors.initials: S
authors.lastname: Ma
authors.forename: Long
authors.initials: L
authors.lastname: Trinh
authors.forename: Runqing
authors.initials: R
authors.lastname: Lu
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology; D002462:Cell Membrane / Q000276:immunology; D049109:Cell Proliferation; D002478:Cells, Cultured; D007136:Immunoglobulins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D050835:Interferon Regulatory Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011485:Protein Binding; D000099218:Interferon Regulatory Factor-4
chemical_list: D001324:Autoantigens; D007136:Immunoglobulins; D050835:Interferon Regulatory Factors; D000099218:Interferon Regulatory Factor-4