title: Inducible gene knockout of transcription factor recombination signal binding protein-J reveals its essential role in T versus B lineage decision.
abstract: The transcription factor recombination signal binding protein-J (RBP-J) functions immediately downstream of the cell surface receptor Notch and mediates transcriptional activation by the intracellular domain of all four kinds of Notch receptors. To investigate the function of RBP-J, we introduced loxP sites on both sides of the RBP-J exons encoding its DNA binding domain. Mice bearing the loxP-flanked RBP-J alleles, RBP-J(f/f), were mated with Mx-Cre transgenic mice and deletional mutation of the RBP-J gene in adult mice was induced by injection of the IFN-alpha inducer poly(I)-poly(C). Here we show that inactivation of RBP-J in bone marrow resulted in a block of T cell development at the earliest stage and increase of B cell development in the thymus. Lymphoid progenitors deficient in RBP-J differentiate into B but not T cells when cultured in 2'-deoxyguanosine-treated fetal thymic lobes by hanging-drop fetal thymus organ culture. Competitive repopulation assay also revealed cell autonomous deficiency of T cell development from bone marrow of RBP-J knockout mouse. Myeloid and B lineage differentiation appears normal in the bone marrow of RBP-J-inactivated mice. These results suggest that RBP-J, probably by mediating Notch signaling, controls T versus B cell fate decision in lymphoid progenitors.
authors.affiliation: Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Hua
authors.initials: H
authors.lastname: Han
authors.forename: Kenji
authors.initials: K
authors.lastname: Tanigaki
authors.forename: Norio
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kuroda
authors.forename: Momoko
authors.initials: M
authors.lastname: Yoshimoto
authors.forename: Tatsutoshi
authors.initials: T
authors.lastname: Nakahata
authors.forename: Koichi
authors.initials: K
authors.lastname: Ikuta
authors.forename: Tasuku
authors.initials: T
authors.lastname: Honjo
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D016026:Bone Marrow Transplantation; D002454:Cell Differentiation; D003114:Colony-Forming Units Assay; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D066298:In Vitro Techniques; D038041:Lymphopoiesis; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009687:Nuclear Proteins; D051880:Receptors, Notch; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D008565:Membrane Proteins; D009687:Nuclear Proteins; C497571:Rbpj protein, mouse; D051880:Receptors, Notch