title: Hematopoietic-specific genes are not induced during in vitro differentiation of scl-null embryonic stem cells.
abstract: The helix-loop-helix transcription factor, scl, plays an essential role in hematopoietic development. Embryos in which the gene has been disrupted fail to develop yolk sac erythropoiesis, and scl-null embryonic stem cells do not contribute to hematopoiesis in chimeric mice. To analyze the molecular consequences of scl deficiency, we compared the gene expression profiles of control (wild-type and scl-heterozygous) and scl-null embryonic stem cells differentiated in vitro for up to 12 days. In control and scl-null embryoid bodies the temporal expression pattern of genes associated with the formation of ventral mesoderm, such as Brachyury, bone morphogenetic protein-4, and flk-1, was identical. Similarly, GATA-2, CD34, and c-kit, which are coexpressed in endothelial and hematopoietic lineages, were expressed normally in scl-null embryonic stem cell lines. However, hematopoietic-restricted genes, including the transcription factors GATA-1, EKLF, and PU.1 as well as globin genes and myeloperoxidase, were only expressed in wild-type and scl-heterozygous embryonic stem cells. Indirect immunofluorescence was used to confirm the observations that GATA-1 and globins were only present in control embryoid bodies but that CD34 was found on both control and scl-null embryoid bodies. These data extend the previous gene ablation studies and support a model whereby scl is absolutely required for commitment of a putative hemangioblast to the hematopoietic lineage but that it is dispensable for endothelial differentiation.
authors.affiliation: The Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Parkville, Victoria, Australia.
authors.forename: A G
authors.initials: AG
authors.lastname: Elefanty
authors.forename: L
authors.initials: L
authors.lastname: Robb
authors.forename: R
authors.initials: R
authors.lastname: Birner
authors.forename: C G
authors.initials: CG
authors.lastname: Begley
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D018952:Antigens, CD34 / Q000235:genetics / Q000502:physiology; D051792:Basic Helix-Loop-Helix Proteins; D002454:Cell Differentiation / Q000235:genetics; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000502:physiology; D050989:GATA2 Transcription Factor; D015870:Gene Expression; D018257:Helix-Loop-Helix Motifs; D006410:Hematopoiesis / Q000235:genetics*; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D060588:LIM Domain Proteins; D008667:Metalloproteins / Q000235:genetics / Q000502:physiology; D051379:Mice; D011518:Proto-Oncogene Proteins; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018952:Antigens, CD34; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D050989:GATA2 Transcription Factor; D060588:LIM Domain Proteins; D008667:Metalloproteins; D011518:Proto-Oncogene Proteins; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; C494712:Gata2 protein, mouse; C513188:Lmo2 protein, mouse; C489366:Tal1 protein, mouse