ORAL-ABORAL AXIS SPECIFICATION IN THE SEA URCHIN EMBRYO

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 科夫曼实验室利用其INBRE支持（启动资金授予詹姆斯科夫曼，PI）进行海胆幼虫的口-口（OA）轴发育规范的机制研究。 轴规范是发育过程中最初的对称性破坏事件，它为生物体的身体平面建立了空间坐标。 基于以前的工作，我们假设，海胆幼虫的OA轴最初是由线粒体在卵和早期胚胎中的不对称分布所建立的氧化还原梯度所指定的，胚胎的一侧继承了最高密度的线粒体，易于激活TGF-β信号分子Nodal的表达，从而发展为口腔外胚层。 我们进一步假设OA极性的特化涉及线粒体H2 O2介导的p38-MAPK的活化，其他人已经证明这是Nodal表达所需的。 在此资助期间，我们已经开始测试这一假设，使用p38-GFP融合蛋白来监测p38活性，并使用神经靶向过氧化氢酶来阻止活胚胎中线粒体H2 O2的排放。 我们发现p38-MAPK活性和Nodal表达之间的关系并不像我们最初假设的那样简单。 虽然p38是明确需要启动节点的表达，我们的数据表明，p38的活性是空间各向同性的早期胚胎在时间的节点激活在圆海胆purpuratus（与以前报道的情况不同的物种的海胆，Lytechinus variegatus）。 尽管如此，初步数据表明，线粒体H2 O2的封锁扰乱规范的OA轴通过节点的表达。 这项INBRE-supported工作提供了初步数据，帮助我们获得了NIEHS R 01研究资助，题为“氧化还原敏感的发育途径和基因调控网络”（ES 016722）。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The Coffman Lab has used its INBRE support (startup funds awarded to James Coffman, PI) to carry out research on the mechanism underlying developmental specification of the oral-aboral (OA) axis of the sea urchin larva. Axis specification is the initial symmetry breaking event in development that sets up the spatial coordinates for the body plan of an organism. Based on previous work, we have hypothesized that the OA axis of the sea urchin larva is initially specified by a redox gradient established by asymmetric distribution of mitochondria in the egg and early embryo, with the side of the embryo inheriting the highest density of mitochondria being pre-disposed to activate expression of the TGF-beta signaling molecule Nodal and thence develop as oral ectoderm. We further hypothesize that the specification of OA polarity involves mitochondrial H2O2-mediated activation of p38-MAPK, which others have shown to be required for Nodal expression. During this funding period we have begun to test this hypothesis, using a p38-GFP fusion protein to monitor p38 activity and mitochondrially-targeted catalase to block emission of mitochondrial H2O2 in live embryos. We have found that the relationship between p38-MAPK activity and Nodal expression is not as simple as we initially hypothesized. Although p38 is clearly required for the initiation of Nodal expression, our data suggest that p38 activity is spatially isotropic in the early embryo at the time of nodal activation in Strongylocentrotus purpuratus (in contrast to the situation previously reported for a different species of sea urchin, Lytechinus variegatus). Nonetheless, preliminary data indicate that blockade of mitochondrial H2O2 does perturb specification of the OA axis via nodal expression. This INBRE-supported work provided preliminary data that helped us obtain (and is now being extended in) a NIEHS R01 research grant entitled "Redox-sensitive developmental pathways and gene regulatory networks" (ES016722).