Abstract：
BACKGROUND: Vertebrate left-right symmetry breaking is preceded by formation of left-right organizer. In Amphibian, this structure is formed by gastrocoel roof plate, which emerges from superficial suprablastoporal cells. GRP is subdivided into medial area, which generates leftward flow by rotating monocilia and lateral Nodal1 expressing areas, which are involved in sensing of the flow. After successful symmetry breaking, medial cells are incorporated into a deep layer where they contribute to the axial mesoderm, while lateral domains join somitic mesoderm.
RESULTS: Here, we performed detailed analysis of spatial and temporal gene expression of important markers and the corresponding morphology of emerging GRP. Endodermal marker Sox17 and markers of superficial mesoderm display complementary patterns at all studied stages. At early stages, GRP forms Tekt2 positive epithelial domain clearly separated from underlying deep layers, while at later stages, this separation disappears. Marker of early somitic mesoderm MyoD1 was absent in emerging GRP and was induced together with Nodal1 during early neurulation. Decreasing morphological separation is accompanied by lateral to medial covering of GRP by endoderm.
CONCLUSIONS: Our data supports continuous link between superficial mesoderm at the start of gastrulation and mature GRP and suggests late induction of somitic fate in lateral GRP.
RESULTS: Here, we performed detailed analysis of spatial and temporal gene expression of important markers and the corresponding morphology of emerging GRP. Endodermal marker Sox17 and markers of superficial mesoderm display complementary patterns at all studied stages. At early stages, GRP forms Tekt2 positive epithelial domain clearly separated from underlying deep layers, while at later stages, this separation disappears. Marker of early somitic mesoderm MyoD1 was absent in emerging GRP and was induced together with Nodal1 during early neurulation. Decreasing morphological separation is accompanied by lateral to medial covering of GRP by endoderm.
CONCLUSIONS: Our data supports continuous link between superficial mesoderm at the start of gastrulation and mature GRP and suggests late induction of somitic fate in lateral GRP.
摘要：
背景：脊椎动物的左右对称破坏之前是左右组织者的形成。在两栖动物中,这种结构是由腹壁顶板形成的，它来自浅表的上鼻孔细胞。GRP被细分为中间区域，通过旋转单纤毛和横向Nodal1表达区域产生向左流动，它们参与了流量的感测。成功打破对称后，内侧细胞被整合到深层，在那里它们有助于轴向中胚层，而侧域加入躯体中胚层。
结果：这里，我们对重要标记的时空基因表达和新兴GRP的相应形态进行了详细分析。内胚层标记物Sox17和浅层中胚层标记物在所有研究阶段都显示出互补的模式。在早期阶段,GRP形成Tekt2阳性上皮结构域与底层深层明显分离，而在后期阶段，这种分离消失了。在新兴的GRP中不存在早期躯体中胚层MyoD1的标记，并且在早期神经形成期间与Nodal1一起被诱导。形态分离的减少伴随着内胚层对GRP的外侧到内侧覆盖。
结论：我们的数据支持原肠胚形成开始时的浅层中胚层与成熟GRP之间的连续联系，并表明在外侧GRP中晚期诱导了躯体命运。
结果：这里，我们对重要标记的时空基因表达和新兴GRP的相应形态进行了详细分析。内胚层标记物Sox17和浅层中胚层标记物在所有研究阶段都显示出互补的模式。在早期阶段,GRP形成Tekt2阳性上皮结构域与底层深层明显分离，而在后期阶段，这种分离消失了。在新兴的GRP中不存在早期躯体中胚层MyoD1的标记，并且在早期神经形成期间与Nodal1一起被诱导。形态分离的减少伴随着内胚层对GRP的外侧到内侧覆盖。
结论：我们的数据支持原肠胚形成开始时的浅层中胚层与成熟GRP之间的连续联系，并表明在外侧GRP中晚期诱导了躯体命运。
