title: A checkpoint in B-lymphopoiesis related to Notch resistance.
abstract: While murine B- and T-lymphopoiesis require overlapping molecules, they occur in separate organs: the bone marrow (BM) and the thymus, respectively. The BM microenvironment is incapable of supporting T-lymphopoiesis because of insufficient interactions of Notch1 with delta-like ligand (Dll). Notch1/Dll interactions also play a role in the suppression of B-lymphopoiesis in the thymus. However, it is still unclear whether the Notch1/Dll interaction alone explains why the thymus does not support B-lymphopoiesis. In this study, we compared the precursor population colonizing the thymus with that in the BM by culturing them on stromal cells expressing abundant Dll1. We demonstrated that Flt3(+) Il7r(+) B220(+) Cd19(+) BM cells gave rise to B cells under this condition. We defined them as resistant to Dll1. In the thymus, Dll1-resistant cells were undetectable. This suggested that the absence of Dll1-resistant cells might explain the absence of B-lymphopoiesis in the thymus.
authors.affiliation: Division of Immunology, Department of Molecular and Cellular Biology, School of Life Science, Faculty of Medicine, Tottori University, Yonago, Tottori, Japan. kazukiok@med.tottori-u.ac.jp
authors.forename: Kazuki
authors.initials: K
authors.lastname: Okuyama
authors.forename: Akihiko
authors.initials: A
authors.lastname: Murata
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Sudo
authors.forename: Miya
authors.initials: M
authors.lastname: Yoshino
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Hayashi
mesh_terms: D000818:Animals; D018941:Antigens, CD19 / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D017493:Leukocyte Common Antigens / Q000378:metabolism; D038041:Lymphopoiesis; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D051881:Receptor, Notch1 / Q000378:metabolism*; D020395:Receptors, Interleukin-7 / Q000378:metabolism; D013950:Thymus Gland / Q000276:immunology*; D051941:fms-Like Tyrosine Kinase 3 / Q000378:metabolism
chemical_list: D018941:Antigens, CD19; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C497762:Notch1 protein, mouse; D051881:Receptor, Notch1; D020395:Receptors, Interleukin-7; C064045:delta protein; C497971:Flt3 protein, mouse; D051941:fms-Like Tyrosine Kinase 3; D017493:Leukocyte Common Antigens