| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2004: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Research Abstract |
Mesoderm cells segregate from primitive streak and diversified into three major population including paraxial, lateral and intermediate type. We attempted to visualize and isolate these types of mesodermal cells in ES cell culture using two types of surface markers, PDGFRα and VEGFR2. Based on the expression pattern of the markers, ES cell-derived mesodermal cells are divided into three population composed of PDGFRα^+, VEGFR2^+(DP), PDGFRα^+, VEGFR2^-(PSP) and PDGFRα^-, VEGFR2^+(VSP). Fate and gene expression analyses have revealed that PSP and VSP show the characteristics of paraxial and lateral mesoderm, respectively. DP could give rise to both PSP and VSP, suggesting that DP contained a common precursor for PSP and VSP. Early gastrula organizer can contribute to another type of mesoderm, axial mesoderm. Goosecoid (Gsc) is a transcriptional factor carrying homeobox and is a ideal candidate of organizer's markers as it is specifically expressed in organizer region during embryogenesis. To visualize the ES cell-derived Gsc-expressing cells, we have generated goosecoid knock-in ES cell using eGFP reporter gene. We tried to establish a suitable condition in the absence of serum and finally found a good culture condition in which almost all of differentiated ES cells were expressing Gsc. Along with the differentiation, Gsc-GFP positive cells were clearly separated into two major populations by the pattern of E-cadherin(ECD) expression. ECD^+ population in Gsc^+ shows endodermal phenotype by cell fate, gene expression and cell morphology. Another population that does not express ECD corresponds to mesoderm lineage and gives rise to the mesodermal descendants such as bone and endothelial cells. A single cell analysis of Gsc^+ cells has identified the mesendodermal progenitors in ES cell culture, which can give rise to endoderm and mesoderm. The current study also has the potential to be useful for understanding molecular event involved in mesodermal differentiation.
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