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.

视网膜及其轴突输出的模式对于视觉功能至关重要，而视网膜直肠作用至关重要 分离是二维神经图发展的经典模型。视网膜神经节细胞获取 沿背腹侧（D-V）和前后（A-P）轴的位置坐标，然后将其翻译 进入轴突引导分子的分级表达，该分子控制着视觉图中的地形分类 地形定位在底面上。从长远来看，我们试图了解轴突的梯度如何 生成Vior。作为第一步，我们在这里提出了对涉及的基因的全面分析 背面视网膜的图案，迄今为止的理解还差。 雏鸡和爪蟾中的Misexpression和主要阴性实验牵涉到BMP4，TBX5， 在背侧规格和D-V地形中，Ephrin-B2。但是，tbx5和ephrin-b2的作用具有 没有通过功能丧失分析来测试，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视网膜模式，这是快速，精确损失的理想选择 研究视网膜模式和视网膜直肠地形的功能实验。主要目标是：（1） 测试已知候选基因BMP4，TBX5和Ephrin-B2所需的作用 命运和地形预测； （2）测试我们已经确定的新候选基因的作用， Cally TCF7，其他TBX基因和Ephrin-B1 \和（3），以鉴定具有正向遗传筛选的新基因 破坏背部视网膜规格的突变体。我们的初步数据首次暗示了Wnt信号 在D-V视网膜模式中，还表明Wnt和BMP途径之间的串扰。 在我们以前在斑马鱼视觉系统方面的专业知识的基础上，我们将结合基因实验 在斑马鱼中可以进行快速而复杂的胚胎学和表型分析。我们将使用前 iSting突变体和反义形态核苷酸核苷酸以及正向基因分离的新突变体 抽动和反向遗传（耕种）遗传筛选。我们将严格测试D-V视网膜的现有模型 通过测试我们的初步数据引起的新假设以及通过测试新的假设，并通过 为所需的基因进行无偏屏幕。这些研究将解决两个基本问题 发育神经生物学：神经系统的区域如何获得位置坐标？和， 然后，他们如何彼此之间建立地形连接？识别背侧视网膜中的关键基因 将为这些基因相互作用以产生地形梯度的相互作用而为将来的工作奠定基础。 与公共卫生有关。视觉系统的发展和结构非常保守 从鱼到人的进化。因此，这些研究将阐明人眼的 形成并变成图案。这是特别感兴趣的，因为背腹眼睛的缺陷 与人类发育障碍（例如coloboma）有关。