Abstract
During early vertebrate embryogenesis, both hematopoietic and endothelial lineages derive from a common progenitor known as the hemangioblast. Hemangioblasts derive from mesodermal cells that migrate from the posterior primitive streak into the extraembryonic yolk sac. In addition to primitive hematopoietic cells, recent evidence revealed that yolk sac hemangioblasts also give rise to tissue-resident macrophages and to definitive hematopoietic stem/progenitor cells. In our previous work, we used a novel hemangioblast-specific reporter to isolate the population of chick yolk sac hemangioblasts and characterize its gene expression profile using microarrays. Here we report the microarray profile analysis and the identification of upregulated genes not yet described in hemangioblasts. These include the solute carrier transporters SLC15A1 and SCL32A1, the cytoskeletal protein RhoGap6, the serine protease CTSG, the transmembrane receptor MRC1, the transcription factors LHX8, CITED4 and PITX1, and the previously uncharacterized gene DIA1R. Expression analysis by in situ hybridization showed that chick DIA1R is expressed not only in yolk sac hemangioblasts but also in particular intraembryonic populations of hemogenic endothelial cells, suggesting a potential role in the hemangioblast-derived hemogenic lineage. Future research into the function of these newly identified genes may reveal novel important regulators of hemangioblast development.
Highlights
During vertebrate embryogenesis, there is a close developmental relationship between hematopoiesis and vasculogenesis
We report the pathway and gene network analysis of the hemangioblast transcriptome and the identification of novel genes expressed in yolk sac hemangioblasts
In chick embryos co-electroporated with hemangioblast-specific enhancer (Hb)-eGFP and the ubiquitous reporter pCAGGS-RFP, eGFP fluorescence is restricted to a population of cells in the posterior extraembryonic region (Figure 1A) and co-localizes with cVEGFR2 (Flk1), a marker of early hemangioblasts (Figure 1B; [23])
Summary
There is a close developmental relationship between hematopoiesis and vasculogenesis. The first hematopoietic and endothelial cells arise in the extraembryonic yolk sac blood islands from a common precursor known as the hemangioblast [1,2]. Cell-tracing studies have shown that these intraembryonic precursors have an extraembryonic origin, as they migrate from the yolk sac prior to the onset of circulation [10,11] Together, these evidences suggest that most (if not all) hematopoietic cells in the embryo derive from yolk sac hemangioblasts. This work introduced the Hb-eGFP reporter as a powerful tool for labeling the hemangioblast population and studying the dynamics of blood island morphogenesis in live imaging assays This reporter was used to describe the transcriptional profile of the hemangioblast [19]. In addition to genes known to have a role in other cell types and developmental processes, we introduce a previously uncharacterized gene, DIA1R, and describe its expression pattern in the chick embryo at different stages of development
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
