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

基本信息

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
项目类别：
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

项目摘要

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育系统稳健地构建正确图案、形状和大小的胚胎。发展系统面临着一系列来自不同来源（包括环境、遗传和随机）的变异，表现在多个方面从分子到细胞再到器官的各个层面。面对这些挑战，生物体被设计出来通过进化缓冲表型免受这些变异的影响，从而稳健地实现发育沃丁顿将这一过程称为运河化。随着我们对分子和细胞细节的了解模式系统已经扩展，现在有机会了解系统级机制从而形成稳健的模式。在这里，我们通过缩放和尺寸控制。缩放是一个非凡的过程，其中可以将图案的尺寸调整为可用的尺寸组织的大小。自汉斯·德里施 (Hans Driesch) 时代以来，缩放一直让胚胎学家着迷又困惑。 1885年发现，当双细胞期海胆胚胎的卵裂球分离时，结果并不两个部分胚胎，而是两个完整的胚胎，其中所有图案都按比例缩小了一半。类似的结果此后已在多种生物体中发现，但产生尺寸所需的外科手术减少动物通常很困难，并且会导致很大的变异性，从而限制了定量研究。最近，我们开发了一种生成不同大小斑马鱼卵的新方法，该方法稳健且可靠可重现。这样的胚胎具有质量正常但有鳞片的图案，并且可以产生可存活的成体。在分子水平上，我们发现大多数基因表达模式（例如形态发生素及其靶标）随他们图案化的组织；然而，一小部分基因，即感知组织大小以调节缩放的基因（例如通过与形态发生素相互作用），不要。因此，这些尺寸改变的胚胎代表了强大且识别和确定模式缩放机制的独特方法。最终，组织尺寸为通过平衡发育过程中的增殖率和分化率来确定。我们有发现神经管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系统级机制，允许：1) 形态发生素图案按比例缩放以适应可用空间，2) 增殖和分化率平衡以使组织生长以适应可用空间。这些问题将在斑马鱼神经管，但我们期望由此产生的机制能够广泛适用。这样一个综合的了解对于诊断和治疗神经管缺陷等出生缺陷以及在工程组织的合理设计。