BMP-like signals are required after the midblastula transition for blood cell development.
We have investigated the process by which the primitive erythroid cells develop during early vertebrate embryogenesis. Cultured Xenopus animal cap (AC) cells transiently activate the transcription of blood cell regulatory genes GATA-1 and GATA-2 but fail to commit stably to the blood lineage. By contrast, cells of the presumptive ventral marginal zone (VMZ), are committed by the midblastula transition (MBT) to express fully on erythroid program. Growth factor BMP-4, a member of the TGF-beta family of signaling molecules, has been implicated in the process of ventral mesoderm patterning. We show that expression of BMP-4 after MBT is sufficient to induce the blood program fully in AC cells. This includes high level expression of the blood markers SCL and globin, which are not activated in AC cells from uninjected embryos. Likewise, expression of a dominant negative receptor after MBT results in relatively normal embryos, which, however, completely lack differentiated blood cells. Our results are consistent with a role for BMP or BMP-like signaling during gastrulation in the differentiation of embryonic blood.
Zhang
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Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Evans
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D000818:Animals; D001483:Base Sequence; D001755:Blastocyst / Q000166:cytology; D052004:Bone Morphogenetic Protein Receptors; D019485:Bone Morphogenetic Proteins; D002454:Cell Differentiation; D002478:Cells, Cultured; D046508:Culture Techniques; D017931:DNA Primers; D004912:Erythrocytes / Q000166:cytology*; D008969:Molecular Sequence Data; D011506:Proteins / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism; D017978:Receptors, Growth Factor; D015398:Signal Transduction / Q000502:physiology*; D014158:Transcription, Genetic; D014981:Xenopus
D019485:Bone Morphogenetic Proteins; D017931:DNA Primers; D011506:Proteins; D011956:Receptors, Cell Surface; D017978:Receptors, Growth Factor; D052004:Bone Morphogenetic Protein Receptors