PATTERNING OF DORSAL RETINA

背侧视网膜的图案化

• 批准号: 7193072
• 负责人: Chi-Bin Chien
• 金额: $ 17.81万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-12-01 至 2011-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7193072
• 关键词: Address; Affect; Anterior; Axon; BMP4; Base Sequence; Biological Assay; Boxing; Brain region; Candidate Disease Gene; Coloboma; Computer information processing; Data; Defect; Development; Dominant-Negative Mutation; Dorsal; Ephrin-B1; Ephrin-B2; Evolution; Eye; Fishes; Future; Gene Expression; Genes; Genetic; Genetic Screening; Genome; Goals; Haploidy; Human; In Situ; In Situ Hybridization; Ions; Knock-out; Knowledge; Larva; Light; Maintenance; Maps; Melanocytic nevus; Modeling; Mole the mammal; Mutant Strains Mice; Nervous system structure; Oligonucleotides; Optic tract structure; Output; Pathway interactions; Pattern; Process; Public Health; Research Personnel; Retina; Retinal; Retinal Ganglion Cells; Role; Screening procedure; Sensory; Signal Transduction; Sorting - Cell Movement; Source; Specific qualifier value; Staging; System; Tectum Mesencephali; Testing; Time; Translating; Vision; Visual system structure; Work; Xenopus; Zebrafish; axon guidance; developmental disease; developmental neurobiology; interest; loss of function; model development; mutant; novel; positional cloning; programs; relating to nervous system; research study; retinal axon; retinotectal; tool; transcription factor; two-dimensional

The patterning of the retina and its axonal output are critical for visual function, and the retinotectal proj- ection is a classic model of the development of two-dimensional neural maps. Retinal ganglion cells acquire positional coordinates along the dorsal-ventral (D-V) and anterior-posterior (A-P) axes, then translate these into graded expression of axon guidance molecules, which control topographic sorting in the optic tract and topographic targeting on the tectum. In the long term, we seek to understand how gradients of axonal beha- vior are generated. As a first step, we propose here a comprehensive analysis of the genes involved in the patterning of dorsal retina, which to date is poorly understood. Misexpression and dominant-negative experiments in chick and Xenopus have implicated BMP4, Tbx5, and ephrin-B2 in dorsal specification and D-V topography. However, the roles of Tbx5 and ephrin-B2 have not been tested by loss-of-function analysis, and our data show that more genes must be involved. We will analyze D-V retinal patterning using the zebrafish visual system, which is ideal for rapid and precise loss- of-function experiments to study retinal patterning and retinotectal topography. The main goals are: (1) to test the required roles of the known candidate genes bmp4, tbx5, and ephrin-B2 in specifying dorsal retinal fate and topographic projections; (2) to test the roles of new candidate genes we have identified, specifi- cally tcf7, other tbx genes, and ephrin-B1\ and (3) to identify new genes with a forward-genetic screen for mutants that disrupt dorsal retinal specification. Our preliminary data implicate Wnt signaling for the first time in D-V retinal patterning, and furthermore suggest crosstalk between the Wnt and BMP pathways. Building on our previous expertise in the zebrafish visual system, we will combine genetic experiments with the rapid and sophisticated embryological and phenotypic analysis possible in zebrafish. We will use ex- isting mutants and antisense morpholino oligonucleotides, as well as new mutants isolated by forward gene- tic and reverse genetic (TILLing) genetic screens. We will critically test the existing model of D-V retinal patterning, and extend it significantly by testing new hypotheses arising from our preliminary data, and by conducting an unbiased screen for required genes. These studies will address two fundamental questions in developmental neurobiology: How do regions of the nervous system acquire positional coordinates? and, How do they then make topographic connections with each other? Identifying the key genes in dorsal retina will lay the groundwork for future work on how these genes interact to generate topographic gradients. Relevance to public health. The development and structure of the visual system are remarkably conserv- ed across evolution from fish to humans. Therefore, these studies will shed light on how the human eye is formed and becomes patterned. This is of particular interest because defects in dorsoventral eye patterning are associated with human developmental disorders such as coloboma.

视网膜的图案及其轴突输出对于视觉功能至关重要，并且视网膜顶盖投影 ection 是二维神经图发展的经典模型。视网膜神经节细胞获得 沿背腹 (D-V) 和前-后 (A-P) 轴的位置坐标，然后平移这些 轴突引导分子的分级表达，其控制视束中的拓扑排序 顶盖上的地形定位。从长远来看，我们试图了解轴突行为的梯度如何 vior 被生成。作为第一步，我们在这里建议对参与的基因进行全面分析 迄今为止，人们对背侧视网膜的图案知之甚少。 小鸡和非洲爪蟾的错误表达和显性失活实验表明 BMP4、Tbx5、 和 ephrin-B2 的背部规格和 D-V 地形。然而，Tbx5 和 ephrin-B2 的作用 尚未经过功能丧失分析测试，我们的数据表明必须涉及更多基因。我们将 使用斑马鱼视觉系统分析 D-V 视网膜图案，这是快速、精确损失的理想选择 研究视网膜图案和视网膜顶盖地形的功能障碍实验。主要目标是：（1） 测试已知候选基因 bmp4、tbx5 和 ephrin-B2 在指定背侧视网膜中所需的作用 命运和地形预测； (2) 为了测试我们已经确定的新候选基因的作用，具体 cally tcf7、其他 tbx 基因和 ephrin-B1\ 和 (3) 通过前向遗传筛选来识别新基因 破坏背侧视网膜规格的突变体。我们的初步数据首次表明 Wnt 信号传导 D-V 视网膜模式，并进一步表明 Wnt 和 BMP 通路之间的串扰。 基于我们之前在斑马鱼视觉系统方面的专业知识，我们将结合遗传实验 可以对斑马鱼进行快速而复杂的胚胎学和表型分析。我们将使用前 现有突变体和反义吗啉代寡核苷酸，以及通过正向基因分离的新突变体 抽动和反向遗传 (TILLing) 遗传筛查。我们将严格测试现有的 D-V 视网膜模型 模式，并通过测试我们初步数据中产生的新假设来显着扩展它，并通过 对所需基因进行公正的筛选。这些研究将解决两个基本问题 发育神经生物学：神经系统区域如何获取位置坐标？和， 那么它们如何相互建立地形联系呢？识别背侧视网膜的关键基因 将为未来研究这些基因如何相互作用产生地形梯度的工作奠定基础。 与公共卫生的相关性。视觉系统的发育和结构非常保守 跨越了从鱼类到人类的进化过程。因此，这些研究将揭示人眼是如何工作的 形成并成为图案。这是特别令人感兴趣的，因为背腹侧眼睛图案的缺陷 与缺损等人类发育障碍有关。