Molecular Mechanisms of Morphogen Gradient Formation

描述(申请人提供)：形态原是在不同的浓度和信号阈值下指定不同细胞命运的分子。这些“形状生成”分子提供了在组织组装过程中生成图案的基本机制。骨形态发生蛋白(BMP)、WNT和Hedgehog生长因子家族的成员，长期以来一直被认为是发育模式所必需的，并参与许多疾病过程，也作为形态发生因子发挥作用。因此，要深入了解组织是如何组装和修复的，就需要深入了解形态生成梯度建立和维持的分子机制。 虽然已经确定硫酸乙酰肝素蛋白多糖(HSPGs)影响由形态生物质指定的构图事件，但直到最近才意识到HSPG本身控制形态生成梯度。Glypicans是一个完整的膜蛋白多糖家族，已知影响从人类到线虫的生长控制和模式。两种果蝇蛋白多糖Dally和Dally-like(DLP)已被证明在翅膀发育过程中控制形态原Dpp(Dpp)、BMP4同源物和Wingless(Wg)。我们对Dally和DLP如何控制形态原梯度提出了详细的生物物理和分子遗传学分析。这些研究包括平行实验，测量这些蛋白多糖与形态因子和形态因子受体的分子相互作用，以及在体内分析它们对发育中翅膀中形态因子分布、信号和周转的影响。Dally和DLP在影响DPP和Wg分布的能力上表现出质的和量的差异，我们希望了解这些差异的分子基础。综上所述，我们提出了以下目标：目的1：利用提供动力学和亲和力数据的各种生物物理方法确定DALY和DLP与形态原和形态受体的物理相互作用；目的2：比较DALY和DLP在影响体内形态原信号和分布方面的差异活性以及这些活性的结构基础；目的3：测量DALY和DLP对体内形态原运动和周转的影响。

DESCRIPTION (provided by applicant): Morphogens are molecules that specify different cell fates at distinct concentration and signaling thresholds. These "form generating" molecules provide a fundamental mechanism of generating pattern during tissue assembly. Members of the bone morphogenetic protein (BMP), Wnt, and Hedgehog families of growth factors, long known to be essential for developmental patterning and involved in many disease processes, also behave as morphogens. An in depth understanding of how tissues are assembled and repaired, therefore, requires insight into the molecular mechanism of morphogen gradient establishment and maintenance. While it has established that heparan sulfate proteoglycans (HSPGs) affect patterning events specified by morphogens, only recently has it been appreciated that HSPGs control morphogen gradients per se. Glypicans are a family of integral membrane proteoglycans known to affect growth control and patterning from humans to nematodes. Two Drosophila proteoglycans, Dally and Dally-like (Dlp), have been shown to control the disposition of the morphogens, Decapentaplegic (Dpp), a BMP4 homolog, and Wingless (Wg), during wing development. We propose a detailed biophysical and molecular genetic analysis of how Dally and Dlp control morphogen gradients. These studies include parallel experiments measuring the molecular interactions of these proteoglycans with morphogens and morphogen receptors, along with in vivo analysis of their effects on morphogen distributions, signaling and turnover in the developing wing. Dally and Dlp show qualitative and quantitative differences in their capacity to affect Dpp and Wg distribution and we wish to understand the molecular basis of these differences. In sum, we propose the following objectives: Aim 1: Determine the physical interaction of Dally and Dlp with morphogens and morphogen receptors using a variety of biophysical measures that provide kinetic and affinity data; Aim 2: Compare the differential activities of Dally and Dlp in affecting morphogen signaling and distribution in vivo and the structural basis of those activities; Aim 3: Measure the effects of Dally and Dlp on morphogen movement and turnover in vivo.