Role of the S97N domain of Dlg in synapse development

描述（由申请人提供）：本申请中提出的研究将主要在智利圣地亚哥的智利大学进行，与Jimena Sierralta博士合作，作为NIH拨款RO1 NS42629的延伸。PI研究的长期目标是通过遗传学方法了解果蝇谷氨酸能神经肌肉连接处突触组装的分子机制。这项研究的一个重要发现是，PSD-95家族中含有pdz的支架蛋白DLG是许多突触蛋白正确定位所必需的。亲本资助的中心目的是表征两个DLG相互作用蛋白Scribble和GUK-holder在突触组装过程中的作用。先前对dig位点的研究发现了一个单一的转录本diga，它存在于突触和上皮细胞中。然而，sierra alta博士最近的研究表明，对起源于挖掘位点的转录本进行了广泛的替代处理。非常有趣的是，一组剪接变体被排除在上皮组织之外，并在神经系统中特异性表达。此外，一个亚型包含一个类似于哺乳动物SAP97的n端延伸，它调节SAP97的定位以及控制SAP97与其伴侣之间结合的分子内相互作用。该合作研究的主要目标是研究这些新的剪接变体在突触形成和成熟的不同方面的作用。这项工作包括研究在突触发育过程中含有$97N结构域的DLG异构体的表达，在突触发育过程中含有$97N结构域的dig基因产物的选择性破坏，以及该结构域在dig与其伴侣结合中的作用。我们设想，国外实验室的观察提供的新维度将极大地增强我们对突触形成过程中DLG的理解，因此将增加在执行亲本拨款过程中获得的知识。

DESCRIPTION (provided by applicant): The research proposed in this application will be primarily performed in Santiago, Chile at the Universidad de Chile in collaboration with Dr. Jimena Sierralta as an extension of NIH grant RO1 NS42629.The long-term goal of the PI's research is to understand the molecular mechanisms by which synapses are assembled using a genetic approach in the glutamatergic neuromuscular junction of Drosophila. An important finding emerging from this investigation is that a PDZ-containing scaffolding protein of the PSD-95 family, DLG, is essentially required to properly localize a number of synaptic proteins. The central aim of the parent grant is to characterize the role of two DLG interacting proteins, Scribble and GUK-holder, in the process of synapse assembly. Previous studies of the dig locus identified the presence of a single transcript, dig-A, which is present both in synapses and epithelial cells. However, recent studies by Dr. Sierralta demonstrate extensive alternative processing of transcripts originated from the dig locus. Very interestingly, a group of splice variants are excluded from epithelial tissue and are specifically expressed in the nervous system. Moreover, a subset of isoforms contains an N-terminal extension similar to mammalian SAP97, which regulates SAP97 localization as well as intramolecular interactions that control the binding between SAP97 and its partners. The main goal of the proposed collaborative research is to investigate the role of these novel splice variants in different aspects of synapse formation and maturation. The work involves the study of the expression of DLG isoforms containing the $97N domain during the development of synapses, the selective disruption of dig gene products containing the $97N domain during synapse development, and the study of the role of this domain in Dig binding to its partners. We envision that the novel dimension provided by the observations in the foreign lab will dramatically enhance our understanding of DLG during synapse formation, and therefore will increase the knowledge obtained during the execution of the parent grant.