title: Cooperative effects of growth factors involved in the induction of hematopoietic mesoderm.
abstract: Hematopoietic induction occurs on the ventral side of Xenopus gastrulae and is thought to be triggered by the growth factor bone morphogenetic protein 4 (BMP-4). To characterize this process, we developed a quantitative and sensitive assay for the induction of erythroid cells from totipotent ectoderm of the embryo. When high doses of BMP-4 were used in this explant assay, few erythroid cells were detected. In contrast, large numbers of differentiated erythroid cells were induced when ectoderm was treated with BMP-4 and the mesoderm inducers, activin, or fibroblast growth factor (FGF). Ectopic expression of GATA-1 also induced abundant erythroid cells in ectoderm treated with bFGF. This induction of erythroid cells by GATA-1 was blocked by coexpression with a dominant negative BMP-4 receptor, showing that GATA-1 requires the BMP signaling cascade to function. These results suggest that BMP-4 requires mesoderm induction to generate a program of gene expression, which regulates the specification of hematopoietic mesoderm by GATA factors.
authors.affiliation: Division of Hematology/Oncology and Howard Hughes Medical Institute, Children's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: T L
authors.initials: TL
authors.lastname: Huber
authors.forename: Y
authors.initials: Y
authors.lastname: Zhou
authors.forename: P E
authors.initials: PE
authors.lastname: Mead
authors.forename: L I
authors.initials: LI
authors.lastname: Zon
mesh_terms: D028341:Activins; D000818:Animals; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D050981:Erythroid-Specific DNA-Binding Factors; D004920:Erythropoiesis / Q000187:drug effects; D005346:Fibroblast Growth Factors / Q000494:pharmacology*; D005775:Gastrula; D006410:Hematopoiesis / Q000187:drug effects* / Q000502:physiology*; D007265:Inhibins / Q000494:pharmacology*; D008648:Mesoderm / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology; D014981:Xenopus / Q000196:embryology / Q000502:physiology*; D029867:Xenopus Proteins
chemical_list: D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D014157:Transcription Factors; D029867:Xenopus Proteins; C525812:bmp4 protein, Xenopus; D028341:Activins; D007265:Inhibins; D005346:Fibroblast Growth Factors