TGFBeta Signaling in Vertebrate Mesoderm Induction

描述(由申请人提供)：本提案涉及TGFbeta的作用 脊椎动物中胚层形成的信号转导。vbl.使用 非洲爪哇胚胎和胚胎外植体在表达背景下的表达 克隆、候选基因方法和微阵列技术，我们有 确定了五个基因，它们通过调节转化生长因子β途径提供了一个强大的 在中胚层形成中的输入。候选基因方法导致了 发现LTBP-1是一种结合和协同作用的组织特异性基因 具有激活素的所有胚胎功能，包括中胚层和次级 轴感应。我建议解决以下问题： LTBP-1与转化生长因子β家族成员的关系及其与组织者的关系 也与激活素结合的特定抑制物，如卵泡抑素，并探索 亲缘家族成员LTBP2和3.功能筛选的进展 导致了OS4的发现，OS4是以前在进化上保守的基因 未知的功能，这也可以诱导中胚层和次级轴。我 建议将os4链接到一条信号通路(S)，首先通过上位法 分析OS4在TGFb途径中的作用，第二通过分离结合 合伙人。我们的非洲爪哇原型微阵列已经识别出大量 激活素调控的cDNA，包括三个新基因。我建议，首先， 以下是这些小说的胚胎学和生化活动 反应基因。第二，我建议使用5000个基因阵列 我的实验室在全球范围内识别基因(包括即时早期反应) 它们受激活素蛋白浓度的不同阈值调节， 其目的是描述和组织临时的剧目 受激活素调控的基因。综上所述，这笔赠款的目的将丰富 我们不仅了解早期脊椎动物中胚层的形成，而且还了解 关于转化生长因子β途径，它与生物学和其他许多领域相关 胚胎学之外的医学。

DESCRIPTION (provided by applicant): This proposal addresses the role of TGFbeta signaling in the formation of the vertebrate mesodermal germ layer. Using Xenopus laevis embryos and embryonic explants in the context of expression cloning, candidate gene approaches and microarray technology, we have identified five genes which, by modulating the TGFbeta pathway provide a strong input in mesoderm formation. The candidate gene approach has lead to the discovery that LTBP-1 is an organizer specific gene which binds and synergizes with all the embryonic functions of activin, including mesoderm and secondary axis induction. I propose to address the specificity of the interaction of LTBP-1 with members of the TGFbeta family, its relationship with organizer specific inhibitors which also bind to activin such as follistatin, and explore the functions of related family members LTBP2 and 3. A gain of function screen has led to the discovery of OS4, an evolutionarily conserved gene of previously unknown function, which is also able to induce mesoderm and secondary axis. I propose to link OS4 to a signaling pathway(s), first by performing an epistatic analysis of OS4 in the TGFB pathway, and second by isolation of binding partners. Our prototype Xenopus microarrays have identified a large number of activin-regulated cDNAs, including three novel genes. I propose, first, to follow on the embryological and biochemical activities of these novel responsive genes. Second, I propose the use of a 5000 gene array available in my laboratory to globally identify genes (including immediate early response) that are regulated by different thresholds of activin protein concentration, with the aim of characterizing and organizing temporally the repertoire of genes regulated by activin. Taken together, the aims of this grant will enrich our knowledge not only about early vertebrate mesoderm formation, but also about the TGFBeta pathway, which is relevant to many other areas of biology and medicine beyond embryology.