Sox17 and Other SoxF-Family Proteins Play Key Roles in the Hematopoiesis of Mouse Embryos.

During mouse development, hematopoietic cells first form in the extraembryonic tissue yolk sac. Hematopoietic stem cells (HSCs), which retain their ability to differentiate into hematopoietic cells for a long time, form intra-aortic hematopoietic cell clusters (IAHCs) in the dorsal aorta at midgestation. These IAHCs emerge from the hemogenic endothelium, which is the common progenitor of hematopoietic cells and endothelial cells.

A Sox17 downstream gene Rasip1 is involved in the hematopoietic activity of intra-aortic hematopoietic clusters in the midgestation mouse embryo.

Background: During mouse embryonic development, definitive hematopoiesis is first detected around embryonic day (E) 10.5 in the aorta-gonad-mesonephros (AGM) region. Hematopoietic stem cells (HSCs) arise in the dorsal aorta's intra-aortic hematopoietic cell clusters (IAHCs).

Sox17-mediated expression of adherent molecules is required for the maintenance of undifferentiated hematopoietic cluster formation in midgestation mouse embryos.

Hematopoietic stem cell-containing intra-aortic hematopoietic cell clusters (IAHCs) emerge in the dorsal aorta of the aorta-gonad-mesonephros (AGM) region during midgestation mouse embryos. We previously showed that transduction of Sox17 in CD45c-Kit cells, which are one component of IAHCs, maintained the cluster formation and the undifferentiated state, but the mechanism of the cluster formation by Sox17 has not been clarified. By microarray gene expression analysis, we found that genes for vascular endothelial-cadherin (VE-cad) and endothelial cell-selective adhesion molecule (ESAM) were expressed at high levels in Sox17-transduced c-Kit cells.