Lineage and cell migration in patterning the limb primordium

肢体原基模式中的谱系和细胞迁移

• 批准号: 8291903
• 负责人: CLIFFORD J. TABIN
• 金额: $ 44.12万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-10 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8291903
• 关键词: Address; Ambystoma; Behavior; Candidate Disease Gene; Cell Differentiation process; Cells; Characteristics; Congenital Abnormality; Data; Defect; Development; Dominant-Negative Mutation; Dorsal; Embryonic Development; Epithelial; Genes; Goals; Growth; Human; Image; Image Analysis; Lateral; Learning; Libraries; Life; Ligands; Limb Bud; Limb Development; Limb structure; Measurement; Mesenchymal; Mesenchyme; Microscopy; Molecular; Morphogenesis; Mus; Mutant Strains Mice; Natural regeneration; Pattern; Play; Population; Primordium; Process; Retroviral Vector; Role; Shapes; Signal Transduction; Staging; Technology; Testing; Time; Tissues; behavior influence; cell behavior; cell motility; cell type; design; directional cell; extracellular; interest; malformation; migration; public health relevance; reconstruction; regenerative; two-photon

DESCRIPTION (provided by applicant): The major objectives of this study is to elucidate the lineage relationships between different cell types and different regionalized populations of cells in the developing limb, to establish patterns of cell movement and migration within the limb primordium, and to determine how lineage and migration are integrated with patterning signals to set the stage for limb morphogenesis. In spite of two decades of intense study on a molecular level, many critical aspects of limb patterning are still not understood. For example, it is not known why the limb bud forms in the place and time that it does. This process involves specific localized epithelial- mesenchymal transition (EMT), but how this is controlled to initiate limb bud formation has not been described. There also have been no studies clarifying why the limb bud grows out as a paddle, flattened along its dorsal- ventral axis, rather than as a hemispherical mound. Moreover, although the normal lineage relationships between different cell types within the limb bud are largely understood, the degree of plasticity in cell differentiation during, for instance, regenerative growth remains controversial. To address these issues we will utilize a range of state-of-the-art approaches including live imaging of cell movements by two-photon microscopy and lineage analysis using tagged libraries of retroviral vectors. Clues to cell behavior identified in these studies will be used to design functional studies of candidate genes that we hypothesize may be involved in regulating cell movements in the limb bud. For example, preliminary data shows that the dynamic expression of different Hox genes correlate with the timing of cells migrating into the limb from the lateral plate. Similarly, there is suggestive evidence that the activity of the secreted ligand Wnt5a plays a role in directing the cell movements leading to flattening of the limb bud into a paddle. Misexpression of wild type, activated, and dominant-negative forms of these genes in conjunction with imaging and analysis of cell migration and of lineage changes, will allow these hypothesis to be directly assessed. PUBLIC HEALTH RELEVANCE: We are studying the contribution of lineage and cell migration to the pattering of the limb bud. Congenital limb malformations are among the most common human birth defects, many, if not most, of which are attributable to defects in the proper establishment of the limb pattern. Moreover, the general lessons we learn about the integration of cellular behavior and extracellular signaling in organizing the limb, will serve as paradigms for understanding these processes during embryogenesis.

描述（由申请人提供）：这项研究的主要目标是阐明发育中肢体中不同细胞类型与不同细胞区域化细胞的不同区域化之间的谱系关系，以建立肢体原始中的细胞运动和迁移模式，并确定谱系和迁移如何与模式信号集成以建立肢体形成的阶段。尽管在分子水平上进行了二十年的深入研究，但肢体模式的许多关键方面仍然尚不清楚。例如，尚不清楚为什么肢体在它所做的位置和时间形成。该过程涉及特定的局部上皮 - 间充质转变（EMT），但是如何控制这是如何控制肢体芽形成的。也没有研究阐明为什么肢体芽随着桨的呈桨，沿着背腹轴扁平，而不是半球形的土墩。此外，尽管在很大程度上了解了肢体芽中不同细胞类型之间的正常谱系关系，但在例如，再生生长期间细胞分化的可塑性程度仍然存在争议。为了解决这些问题，我们将利用一系列最新方法，包括通过两光子显微镜和谱系分析对细胞运动进行实时成像，并使用逆转录病毒载体的标记库进行分析。这些研究中鉴定出的细胞行为的线索将用于设计我们假设的候选基因的功能研究，这些研究可能与调节肢体芽中的细胞运动有关。例如，初步数据表明，不同HOX基因的动态表达与从侧板迁移到肢体的细胞时机相关。同样，有暗示性的证据表明，分泌的配体Wnt5a的活性在指导细胞运动中起作用，导致肢体芽变平到桨中。这些基因的野生型，激活和显性阴性形式的表现以及对细胞迁移和谱系变化的成像和分析的结合，将可以直接评估这些假设。 公共卫生相关性：我们正在研究谱系和细胞迁移对肢体芽的构图的贡献。先天性肢体畸形是人类最常见的先天缺陷之一，其中许多（如果不是大多数）是归因于肢体模式适当建立的缺陷。此外，我们了解组织肢体中细胞行为和细胞外信号传导的整合的一般课程，将作为在胚胎发生过程中理解这些过程的范式。