title: Molecular dissection of prethymic progenitor entry into the T lymphocyte developmental pathway.
abstract: Notch signaling activates T lineage differentiation from hemopoietic progenitors, but relatively few regulators that initiate this program have been identified, e.g., GATA3 and T cell factor-1 (TCF-1) (gene name Tcf7). To identify additional regulators of T cell specification, a cDNA library from mouse Pro-T cells was screened for genes that are specifically up-regulated in intrathymic T cell precursors as compared with myeloid progenitors. Over 90 genes of interest were identified, and 35 of 44 tested were confirmed to be more highly expressed in T lineage precursors relative to precursors of B and/or myeloid lineage. To a remarkable extent, however, expression of these T lineage-enriched genes, including zinc finger transcription factor, helicase, and signaling adaptor genes, was also shared by stem cells (Lin(-)Sca-1(+)Kit(+)CD27(-)) and multipotent progenitors (Lin(-)Sca-1(+)Kit(+)CD27(+)), although down-regulated in other lineages. Thus, a major fraction of these early T lineage genes are a regulatory legacy from stem cells. The few genes sharply up-regulated between multipotent progenitors and Pro-T cell stages included those encoding transcription factors Bcl11b, TCF-1 (Tcf7), and HEBalt, Notch target Deltex1, Deltex3L, Fkbp5, Eva1, and Tmem131. Like GATA3 and Deltex1, Bcl11b, Fkbp5, and Eva1 were dependent on Notch/Delta signaling for induction in fetal liver precursors, but only Bcl11b and HEBalt were up-regulated between the first two stages of intrathymic T cell development (double negative 1 and double negative 2) corresponding to T lineage specification. Bcl11b was uniquely T lineage restricted and induced by Notch/Delta signaling specifically upon entry into the T lineage differentiation pathway.
authors.affiliation: Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: C Chace
authors.initials: CC
authors.lastname: Tydell
authors.forename: Elizabeth-Sharon
authors.initials: ES
authors.lastname: David-Fung
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Moore
authors.forename: Lee
authors.initials: L
authors.lastname: Rowen
authors.forename: Tom
authors.initials: T
authors.lastname: Taghon
authors.forename: Ellen V
authors.initials: EV
authors.lastname: Rothenberg
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology*; D019070:Cell Lineage / Q000235:genetics / Q000276:immunology*; D002478:Cells, Cultured; D018920:Coculture Techniques; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D005333:Fetus; D020869:Gene Expression Profiling; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D038041:Lymphopoiesis / Q000235:genetics / Q000276:immunology*; D008565:Membrane Proteins / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D051880:Receptors, Notch / Q000502:physiology; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology
chemical_list: C511143:Bcl11b protein, mouse; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D051880:Receptors, Notch; D012097:Repressor Proteins; D025521:Tumor Suppressor Proteins; C064045:delta protein