The roles of Gbeta5 and R7 RGS protein in vision

Gbeta5和R7 RGS蛋白在视觉中的作用

• 批准号: 8395989
• 负责人: Ching-Kang Jason Chen
• 金额: $ 37.38万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8395989
• 关键词: Adult; Affect; Amacrine Cells; Area; Biochemistry; Biological Preservation; Birth; Brain; Cell membrane; Cell physiology; Cells; Cellular Structures; Defect; Dendrites; Dendritic Cells; Development; Disease; Electron Microscopy; Electrophysiology (science); Electroretinography; Future; GTP-Binding Protein Regulators; GTP-Binding Proteins; Genes; Genetic; Goals; Heterotrimeric GTP-Binding Proteins; Histology; Human; Inherited; Investigation; Knock-in Mouse; Knock-out; Knowledge; Light; Link; Measures; Mediating; Membrane Potentials; Modality; Molecular Biology; Morphology; Mus; Mutation; Nature; Night Blindness; Partner in relationship; Patients; Photoreceptors; Phototransduction; Prevention; Property; RGS Proteins; Recovery; Regulation; Retina; Retinal; Retinal Diseases; Role; Signal Transduction; Staging; Synapses; System; Tamoxifen; Testing; Therapeutic; Time; Transgenic Mice; Vertebrate Photoreceptors; Vision; Visual; Visual system structure; Work; base; cholinergic; critical period; functional restoration; genetic manipulation; improved; insight; knowledge base; neurotransmission; novel; outer plexiform layer; patch clamp; postnatal; response; restoration; retinal neuron; retinal rods; retinogeniculate; ribbon synapse; synaptogenesis; vision development; visual information

DESCRIPTION (provided by applicant): Signal transduction mediated by heterotrimeric G-proteins occurs throughout nature and is best represented by phototransduction in retinal rods. However, how trimeric G-proteins subserve vertebrate vision outside photoreceptors is still poorly understood. This application will fill this gap by elucidating the roles of the fifth Gb subnit (Gb5) and its obligate partners R7 Regulators of G-protein Signaling (RGS6, RGS7, RGS9, RGS11) in mouse retina. The proposal is based on defects found in the visual system of Gb5-/-mice, which include: 1) infrequent spontaneous retinal waves~ 2) poorly refined retinogeniculate projections~ 3) abnormal ribbon synapses at outer plexiform layer (OPL) with unincorporated depolarizing bipolar cells (DBC) dendrites~ 4) lack of electroretinography (ERG) b-waves~ 5) reduction of starburst amacrine cell (SAC) dendritic field, 6) rhythmic oscillation SAC membrane potentials, and 7) prolonged phototransduction recovery. We demonstrate that Gb5 works exclusively through stabilizing R7 RGS proteins in retina and hence in its absence the signaling state of Gbo is hypothesized to be pathologically prolonged to cause these visual defects. Furthermore, we find that the requirement of Gb5 and R7 RGS for normal DBC function takes place during retinal development and that Gb5 may be very slowly turned over at dendritic tips of adult DBC. Solving the underlying mechanism(s) of the aforementioned defects will thus advance knowledge concerning the development and function of retina. We propose here to use an integrated approach combining molecular biology, biochemistry, histology, mouse genetics, ERG, and single cell electrophysiology to achieve the following goals. Aim-1 will test whether prolonged Gbo signaling retards formation of OPL triadic ribbon synapses in Gb5-/- mice. Aim-2 will define a critical period during which Gb5 and R7 RGS proteins are needed for visual system development. It will also measure the stability of OPL synapse and turnover rate of Gb5, Gbo, Gb13 and R7 RGS proteins in DBC. Aim- 3 will examine which and how R7 RGS proteins are involved in stage II cholinergic retinal waves, whether prolonged Gbo activation underlies the reduction of SAC dendritic fields, and the synaptic origin and oscillatory mechanism of adult Gb5-/- SAC. By completing these aims we shall know which and how trimeric G-proteins are used in vision beyond phototransduction in different retinal neurons. Useful mouse lines will be made here and characterized to facilitate future inquiry of the applicability of newly gained knowledge in the retina to central visual system and/or other CNS circuits. Finally, knowing the normal visual mechanism is indispensable for efficient prevention, preservation, and restoration of vision in patients suffering from various debilitating blinding diseases. PUBLIC HEALTH RELEVANCE: Retinal neurons downstream of photoreceptors compute and relay visual information to brain. Many hereditary human blinding diseases affect not only photoreceptors but also downstream retinal neurons. The application seeks to advance knowledge on the roles of heterotrimeric G-proteins in retina beyond phototransduction of photoreceptors and to strengthen the knowledge base to provide novel treatment and therapeutic modalities to improve or preserve human vision.

描述（由申请人提供）：异三聚体G蛋白介导的信号转导贯穿整个自然，并且最好由视网膜杆的光转传表示。然而，三聚体G蛋白如何在光感受器之外提供脊椎动物视觉仍然很少了解。该应用程序将通过阐明第五GB子NIT（GB5）的作用及其专性合作伙伴R7信号传导（RGS6，RGS7，RGS9，RGS9，RGS11）在小鼠视网膜中的作用来填补这一空白。该提案基于在GB5 - / - 小鼠的视觉系统中发现的缺陷，其中包括：1）无常见的自发性视网膜波〜2）不良精炼的视网膜生成型突起〜3）外部乘正交层异常的丝带突触（OPL）与未完成的DEMalalial demalalial demalalial demalliale双极细胞（dbc）dbc（dbc）deDendries indendrave（dbc）dendendravy 〜4 〜4〜） 5）减少星状爆炸性小骨细胞（SAC）树突状场，6）节奏振荡囊囊膜电位，以及7）延长的光转传回收率。我们证明，GB5仅通过在视网膜中稳定R7 RGS蛋白而起作用，因此在缺乏GBO的信号传导状态在病理上延长以引起这些视觉缺陷。此外，我们发现GB5和R7 RGS对正常DBC功能的需求发生在视网膜发育过程中，并且在成人DBC的树突状尖端，GB5可能会非常缓慢地翻转。因此，解决上述缺陷的基本机制将提高有关视网膜发展和功能的知识。我们在这里建议使用一种结合分子生物学，生物化学，组织学，小鼠遗传学，ERG和单细胞电生理学的综合方法来实现以下目标。 AIM-1将测试GBO信号延长的GBO信号延迟在GB5 - / - 小鼠中的OPL三联丝带突触的形成。 AIM-2将定义一个关键时期，在此期间，为了视觉系统开发需要GB5和R7 RGS蛋白。它还将测量DBC中OPL突触的稳定性和GB5，GBO，GB13和R7 RGS蛋白的稳定性。 AIM-3将检查R7 RGS蛋白如何参与II期胆碱能视网膜波，长期GBO激活是否构成了SAC树突状场的减少以及成年GB5 - / - SAC的突触起源和振荡机制。通过完成这些目标，我们将知道在不同视网膜神经元中光转导的视觉中如何使用三聚体G蛋白。将在此处制作有用的小鼠线，并进行表征，以促进将来对视网膜中新获得的知识和中央视觉系统和/或其他CNS电路的适用性的调查。最后，了解正常的视觉机制对于患有各种令人衰弱的盲目疾病的患者的有效预防，保存和视力恢复是必不可少的。 公共卫生相关性：感光体下游的视网膜神经元计算和继电器视觉信息到大脑。 许多遗传性人类盲疾病不仅影响感光因子，而且会影响下游的视网膜神经元。该应用程序旨在提高有关异源三聚体G蛋白在视网膜中的作用的知识，而不是光感受器的光转导，并加强知识库，以提供新颖的治疗和治疗方式，以改善或维护人类的视力。