Induction assay, hematopoiesis

Transgenic Embryo Explant Culture Assay for Induction of Hematopoiesis by Non-Mesodermal Signals... 

To establish more directly that visceral endoderm is required for induction of hematopoiesis in the gastrulating embryo, tissue recombination experiments were performed. A semi-quantitative RT-PCR protocol was used to assay for activation of the endogenous mouse embryonic p-like globin genes (15), Ectoderm and VE layers from individual embryos were cultured separately or in combination for two to four days. RNA was prepared from individual explants and analyzed for embryonic globin gene activation using the RT-PCR assay. 

Might the molecules responsible for respecification of cell fate observed in the reprogramming assay be distinct from those involved in activation of hematopoiesis from nascent posterior mesoderm in vfvol The induction (epiblast explant) assay presumably reflects what occurs in vivo, while the reprogramming (anterior ectoderm) assay reflects the potential activity of visceral endoderm signals. Anterior ectoderm is normally fated to form neurectoderm, not blood or endothelial cells. 

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