A soluble form of human Delta-like-1 inhibits differentiation of hematopoietic progenitor cells.
Two Notch ligand families, Delta and Serrate/Jagged, have been identified in vertebrates. Members of the Jagged family have been shown to affect in vitro hematopoiesis. To determine whether members of the Delta family might play a similar role in hematopoiesis, we examined the expression of mouse Delta-like-1 (mDll1). mDll1 protein was detected in whole marrow and in a marrow stromal cell line MS-5. At the RNA level, both mDll1 and Notch1 were seen in marrow precursor, differentiated hematopoietic, marrow stromal, and MS-5 cells. We isolated a cDNA encoding the human homologue of mDll1, designated human Delta-like-1 (hDll1). A soluble form of hDll1, hDll1(NDSL), containing the DSL domain and the N-terminal sequences, was expressed and purified from bacteria as a glutathione S-transferase (GST) fusion protein. We observed that hDll1(NDSL) delayed the acquisition of differentiation markers by murine hematopoietic progenitor cells (Lin-) cultured in vitro with cytokines. In addition, it promoted greater expansion (more than 3 times) of the primitive hematopoietic precursor cell population, measured in high-proliferative potential colony assay and day 12 colony-forming unit spleen (CFU-S) assay, than GST controls. We also observed that the percentage of apoptotic cells decreased and that the number of cells in the S-phase of the cell cycle increased in the cultures of Lin(-) cells with hDll1(NDSL). The effects of hDll1(NDSL) were blocked by antibody against the mouse counterpart of hDll1(NDSL), mDll1(NDSL). These observations demonstrate that hDll1 plays a role in mediating cell fate decisions during hematopoiesis. (Blood. 2000;95:1616-1625)
Han
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Laboratory of Developmental Hematopoiesis, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Ye
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Moore
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D000595:Amino Acid Sequence; D000818:Animals; D000943:Antigens, Differentiation / Q000032:analysis; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D003114:Colony-Forming Units Assay; D018076:DNA, Complementary / Q000235:genetics; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000187:drug effects; D006410:Hematopoiesis / Q000187:drug effects / Q000502:physiology*; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000096:biosynthesis; D051880:Receptors, Notch; D011993:Recombinant Fusion Proteins / Q000502:physiology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D017154:Stromal Cells / Q000378:metabolism
D000943:Antigens, Differentiation; D018076:DNA, Complementary; D016298:Hematopoietic Cell Growth Factors; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D051880:Receptors, Notch; D011993:Recombinant Fusion Proteins; C064045:delta protein