Dynamic regulatory mechanisms of robust pattern formation in the neural tube

神经管中稳健模式形成的动态调节机制

• 批准号: 10162614
• 负责人: SEAN G MEGASON
• 金额: $ 33.55万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-13 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10162614
• 关键词: Address; Adult; Animals; Back; Buffers; Cell Separation; Cell Shape; Cell division; Cells; Code; Complex; Computer Models; Congenital Abnormality; Data; Degenerative Disorder; Development; Developmental Biology; Diagnosis; Diffuse; Disease; Dose; Dysmorphology; Embryo; Embryology; Equilibrium; Evolution; Face; Feedback; Feeds; Foundations; Funding; Gene Dosage; Gene Expression Profile; Genes; Genetic; Glean; Goals; Grant; Growth; Image; Image Analysis; Investigation; Knowledge; Malignant Neoplasms; Mechanics; Methodology; Methods; Modeling; Molecular; Neural Tube Defects; Neural tube; Noise; Operative Surgical Procedures; Organ; Organism; Pattern; Pattern Formation; Phenotype; Positioning Attribute; Process; Proteins; Publishing; Quantitative Microscopy; Regulator Genes; Reproducibility; Research; SHH gene; Sea Urchins; Shapes; Signal Transduction; Site; Somites; Source; Specific qualifier value; System; Testing; Time; Tissue Engineering; Tissues; To specify; Variant; Work; Zebrafish; base; beta catenin; biophysical properties; cell type; course development; design; egg; embryo stage 2; engineering design; expectation; fascinate; insight; interest; lens; mathematical model; mechanical pressure; morphogens; mutant; neural patterning; notch protein; notochord; prevent; quantitative imaging; response

Abstract The long-term goal of our research is to understand the principles that permit developmental systems to robustly construct embryos of the correct pattern, shape, and size. Developmental systems face a gamut of variations from different sources including environmental, genetic, and stochastic, which manifest at multiple levels from molecules to cells to organs. In the face of these challenges, organisms have been designed through evolution to buffer the phenotype against these variations in order to robustly achieve a developmental norm, a process Waddington termed canalization. As our knowledge of the molecular and cellular details of patterning systems has expanded, there is now the opportunity to understand the systems level mechanisms that give rise to robust pattern formation. Here we focus on pattern robustness through the lens of scaling and size control. Scaling is a remarkable process in which the size of a pattern can be adjusted to the available size of the tissue. Scaling has fascinated and baffled embryologists since the time of Hans Driesch who in 1885 found that when the blastomeres of a two-cell stage sea urchin embryo are separated, the result is not two partial embryos but rather two complete embryos in which all their pattern is scaled by half. Similar results have since been found in a variety of organisms, but the surgical manipulations required to generate size- reduced animals are generally difficult and result in a lot of variability, thus limiting quantitative investigation. Recently, we have developed a new method for generating zebrafish eggs of different size that is robust and reproducible. Such embryos have qualitatively normal but scaled patterning and can give rise to viable adults. At a molecular level we find that most gene expression patterns (e.g. morphogens and their targets) scale with the tissues they pattern; however, a small subset of genes, the ones that sense tissue size to regulate scaling (e.g. by interacting with morphogens), do not. Thus, these size altered embryos represent a powerful and unique method to identify and determine the mechanisms of pattern scaling. Ultimately, tissue size is determined by balancing the rates of proliferation and differentiation over the course of development. We have found that the balance of proliferation and differentiation in the neural tube is under negative feedback control by mechanical pressure/tissue packing. Here we will use a combination of quantitative imaging, molecular and mechanical perturbations, and computer modeling to determine the systems-level mechanisms that allow: 1) morphogen patterning to scale to fit the available space, and 2) proliferation and differentiation rates to be balanced to cause a tissue to grow to fit the available space. These questions will be addressed in the zebrafish neural tube, but we expect the resulting mechanisms to be widely applicable. Such an integrated understanding is important for diagnosing and treating birth defects such as neural tube defects and in the rational design of engineered tissues.

抽象的 我们研究的长期目标是了解允许发展系统的原则 稳健地构造正确的图案，形状和大小的胚胎。发展系统面临 来自环境，遗传和随机的不同来源的变化，这些变化表现为多个 从分子到细胞再到器官的水平。面对这些挑战，已经设计了生物 通过进化，以缓冲表型，以防止这些变化，以便稳健地实现发展 规范，瓦丁顿的过程称为载口。作为我们对分子和细胞细节的了解 图案系统已经扩展，现在有机会了解系统级机制 这引起了强大的模式形成。在这里，我们通过缩放镜头和 尺寸控制。缩放是一个了不起的过程，可以将图案的大小调整为可用的 组织的大小。自从汉斯·迪尔斯（Hans Driesch）时代以来 1885年发现，当两细胞阶段海胆胚胎分离时，结果不是 两个部分胚胎，而是两个完整的胚胎，其中所有图案都缩小了一半。相似的结果 此后在各种生物中都发现了，但是产生大小所需的手术操作 减少动物通常很困难，并且导致很多可变性，从而限制了定量研究。 最近，我们开发了一种新方法来产生不同尺寸的斑马鱼卵，这种卵很健壮，并且 可再现。这种胚胎具有质性的正常，但缩放了图案，可以产生可行的成年人。 在分子水平上，我们发现大多数基因表达模式（例如形态元素及其靶标）尺寸 它们形成的组织；但是，一小部分基因，那些感知组织大小调节缩放的基因 （例如，通过与形态剂相互作用），不要。因此，这些大小改变的胚胎代表了一个强大的 识别和确定模式缩放机制的独特方法。最终，组织大小为 通过平衡发展过程中的增殖和差异速率来确定。我们有 发现神经管中增殖和分化的平衡处于负反馈控制之下 通过机械压力/组织包装。在这里，我们将结合定量成像，分子和 机械扰动和计算机建模以确定允许的系统级机制：1） 形态学模式以扩展可用空间，2）扩散和分化速率为 平衡以使组织生长以适合可用空间。这些问题将在 斑马鱼神经管，但我们预计由此产生的机制将广泛适用。这样的整合 理解对于诊断和治疗先天缺陷，例如神经管缺陷以及在 工程组织的合理设计。