title: Low SCL/TAL1 expression reveals its major role in adult hematopoietic myeloid progenitors and stem cells.
abstract: Stem cell leukemia/T cell acute leukemia 1 (SCL/TAL1) plays a key role in the development of murine primitive hematopoiesis but its functions in adult definitive hematopoiesis are still unclear. Using lentiviral delivery of TAL1-directed shRNA in human hematopoietic cells, we show that decreased expression of TAL1 induced major disorders at different levels of adult hematopoietic cell development. Erythroid and myeloid cell production in cultures was dramatically decreased in TAL1-directed shRNA-expressing cells, whereas lymphoid B-cell development was normal. These results confirm the role of TAL1 in the erythroid compartment and show TLA1's implication in the function of myeloid committed progenitors. Moreover, long-term cultures and transplantation of TAL1-directed shRNA-expressing CD34+ cells into irradiated nonobese diabetic-severe combined immunodeficient (NOD-SCID) mice led to dramatically low levels of human cells of all lineages including the B-lymphoid lineage, strongly suggesting that TAL1 has a role in the early commitment of hematopoietic stem cells (HSCs) in humans. Cultures and transplantation experiments performed with mouse Sca1+ cells gave identical results. Altogether, these observations definitively show that TAL1 participates in the regulation of hematopoiesis from HSCs to myeloid progenitors, and pinpoint TAL1 as a master protein of human and murine adult hematopoiesis.
authors.affiliation: Département d'Hématologie, Institut Cochin, Paris, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Brunet de la Grange
authors.forename: Florence
authors.initials: F
authors.lastname: Armstrong
authors.forename: Veronique
authors.initials: V
authors.lastname: Duval
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Rouyez
authors.forename: Nicolas
authors.initials: N
authors.lastname: Goardon
authors.forename: Paul-Henri
authors.initials: PH
authors.lastname: Romeo
authors.forename: Françoise
authors.initials: F
authors.lastname: Pflumio
mesh_terms: D000328:Adult; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D018929:Cell Culture Techniques; D003114:Colony-Forming Units Assay; D005786:Gene Expression Regulation; D006410:Hematopoiesis / Q000276:immunology / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D006801:Humans; D007223:Infant; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D016688:Mice, Inbred NOD; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D013234:Stem Cells / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D015514:Oncogene Proteins, Fusion; C103486:SIL protein, mouse; C071236:STIL protein, human