The Roles of LIM-Homeodomain Transcription Factors in Retinal Development

LIM-同源域转录因子在视网膜发育中的作用

• 批准号: 9082149
• 负责人: Lin Gan
• 金额: $ 38.38万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-01 至 2021-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9082149
• 关键词: Amacrine Cells; Axon; Blindness; Cell Differentiation process; Cell Lineage; Cells; ChIP-seq; Characteristics; Contrast Sensitivity; Coupled; Data; Dendrites; Detection; Development; Dyes; Electrophysiology (science); Event; Failure; Family; Ganglia; Ganglion Cell Layer; Gene Targeting; Genes; Genetic; Individual; Injection of therapeutic agent; Inner Nuclear Layer; Inner Plexiform Layer; Knock-in; LHX2 gene; Link; Location; Massive Parallel Sequencing; Mediating; Molecular; Morphology; Mus; Nervous system structure; Neuraxis; Neurons; Pathway interactions; Pattern; Photoreceptors; Play; Process; Property; Proteins; Regulatory Pathway; Reporter; Retina; Retinal; Retinal Cone; Retinal Defect; Role; Shotgun Sequencing; Stratification; Structure; Subgroup; Synapses; Technology; Vision; Visual Perception; Visual impairment; base; cell type; chromatin immunoprecipitation; homeodomain; in vivo; interest; member; neural circuit; novel; null mutation; object motion; patch clamp; public health relevance; recombinase; retinal neuron; retinal rods; retinogenesis; transcription factor; transcriptome; transcriptome sequencing; visual information; visual process; visual processing

 DESCRIPTION (provided by applicant): Our accurate vision depends on the flow of visual information through precisely wired synaptic connections among axons and dendrites of retinal neurons with unique morphological and functional properties. In the vertebrate retina, each of the six neuronal cell types: ganglion, amacrine, bipolar, horizontal, and rod and cone photoreceptor cells are further divided into subtypes based on location, morphology and function. Of all retinal neurons, amacrine cells are the most diverse group with >30 subtypes being identified so far. They represent ~40% of neurons both in the inner nuclear layer (INL) and the ganglion cell layer (GCL), make up a majority of synapses in the inner plexiform layer (IPL), and contribute to a majority of visual processing in the retina. One of the key questions i how the many retinal neuronal subtypes are produced and wired during development. In this proposal, we focus on the amacrine cells associated with the sublaminar layer 3 (S3) of the IPL. The S3 sublamina separates the ON and OFF laminas in the IPL but its cellular makeup and function is poorly understood. Here, we have demonstrated LHX9, a LIM-homeodomain transcription factor, is expressed early in retinogenesis and its expression is tightly confined toa few amacrine cells in the INL and the GCL. In our preliminary study, we have shown that these LHX9+ cells are a subgroup of GABAergic amacrine cells and express GAD67 but not GAD65. LHX9-expressing cells are also LHX2-expressing subgroup of amacrine cells. Targeted deletion of Lhx9 in mice results in a nearly complete loss of these LHX2-expressing amacrine cells and strikingly, in the absence of the S3 sublamina, suggesting that LHX9 could be expressed in and be required for the development of a unique, S3-stratifying amacrine subtype cells. Interestingly, our preliminary data show that bNOS expression is significantly down-regulated in the Lhx9-null retina, suggesting a loss of bNOS-subtype of amacrine cells that are known to project in the S3 sublamina. Being a transcription factor with a known function in neuronal subtype development in the central nervous system, LHX9 likely plays a critic role in amacrine subtype specification and offers us a unique opportunity to ultimately elucidate the genetic pathway governing the formation of the S3 sublamina and its associated neural circuitry. In this proposal, we will fully characterize the subtype identity of these LHX9-expressing amacrine subtypes and will identify its circuitry within the retina. Second, we will analyze the retinal defects of Lhx9-null mutation, particularly the effect on amacrine subtype specification, differentiation of these Lhx9-expressing S3 stratifying amacrine cells, and the change in the functional properties and circuitry of the Lhx9-lineage cells. To elucidate the LHX9 regulatory pathway in the S3-stratifying amacrine cells, we will perform RNA-Seq of control and Lhx9-null retinas and use LHX9 ChIP-Seq to screen for downstream target genes of LHX9 and to identify the transcriptional network. Together, these studies will define the role of LHX9 in regulating the formation and neural circuitry of S3 sublamina and elucidate the transcriptional events that occur downstream of LHX9.

 描述（由适用提供）：我们的准确视觉取决于通过具有独特形态和功能特性的残留神经元的轴突和树突之间精确有线的突触连接的视觉信息流。在脊椎动物视网膜中，六种神经元细胞类型中的每一种：神经节，肌氨酸，双极，水平，杆和锥形感光细胞基于位置，形态和功能进一步分为亚型。在所有残留神经元中，无长链细胞是迄今为止识别出> 30个亚型的最潜水员组。它们代表内部核层（INL）和神经节细胞层（GCL）中的神经元的约40％，在内部丛状层（IPL）中占大多数突触，并在视网膜中有助于大多数视觉处理。我在开发过程中如何产生和连接的许多残留神经元亚型的关键问题之一。在此提案中，我们专注于与IPL的Sublaminar第3层（S3）相关的浸润液细胞。 S3 Sublamina在IPL中分离了开孔和关闭层片，但其细胞构成和功能知之甚少。在这里，我们已经证明了LHX9是一种lim瘤域转录因子，在视网膜生成早期表达，其表达紧密地限制在​​INL和GCL中的木氯酸酯细胞很少。在我们的初步研究中，我们表明这些LHX9+细胞是Gabaergic amaccrene细胞的亚组，并表达GAD67，但不能表达GAD65。表达LHX9的细胞也是表达LHX2的木磷酸细胞的亚组。小鼠中LHX9的靶向删除导致这些表达LHX2表达的浸润液细胞几乎完全丢失，并且在没有S3 sublamina的情况下引人注目，这表明LHX9可能会在其中表达出来，并且需要开发独特的S3-压缩的木氯六氯化湿度下的图表，以表达出来，以表现出明显的bn tyos，以表达出来的bnos the，这是bn的bnos the bneos the bn tyos to bn tyos to bn LHX9-null视网膜，表明已知在S3 Sublamina中预测的无肿大细胞的BNO-subtype丧失。作为中枢神经系统中神经元亚型发育具有已知功能的转录因子，LHX9可能在无链氨酸亚型规范中起关键作用，并为我们提供了一个独特的机会，可以最终阐明管理S3 Sublamina及其相关神经回路的通用途径。在此提案中，我们将充分表征这些表达LHX9的无链氨酸亚型的亚型身份，并将确定其在视网膜内的电路。其次，我们将分析LHX9-NULL突变的残余缺陷， 特别是对无长血性亚型规范的影响，这些表达LHX9的S3分层的无长血管细胞的分化，以及LHX9-Lineage细胞的功能特性和电路的变化。阐明S3分离的LHX9调节途径 无小细胞，我们将执行对照和LHX9-NULL视网膜的RNA-Seq，并使用LHX9芯片seq筛选LHX9的下游目标基因并识别转录网络。总之，这些研究将定义LHX9在确定S3 Sublamina的形成和神经回路中的作用，并阐明LHX9下游发生的转录事件。