SYNAPTIC CONNECTIVITY IN CENTRAL BRAIN

这项提议的总体目标是描述建立和调节中枢中间神经元之间突触的分子机制。我们将通过(1)进一步表征果蝇Pou结构域转录调控因子Acj6的功能及其在中央脑建立正确突触连接中的作用，(2)确定在突触形成过程中受Acj6调控的途径(S)的其他成分，以及(3)表征氨基末端Acj6 POUIV盒在调节Acj6功能中的作用。该建议的具体实施包括：(1)通过完成对acj6突变表型增强子和抑制子的遗传筛选，鉴定受acj6调控的途径(S)的其他组件；(2)通过产生Acj6神经元特异性表达转座子，进一步鉴定Acj6突变体在突触连接方面的缺陷；(3)鉴定由氨基端POUIV盒选择性剪接产生的Acj6异构体的神经元特异性表达；以及(4)完成酵母双杂交筛选与Acj6 POUIV盒相互作用的异源蛋白。突触发生的过程需要对正确的突触伙伴进行精确的初始选择，并随后对终末过程和连接进行改进。这种突触选择、提炼、强化和/或消除的过程被认为是学习和记忆形成的重要过程，可能是许多神经病理的根源。对果蝇突触功能的遗传分析对我们学习和记忆机制的了解做出了重大贡献。在初步研究中，我们已经证明了果蝇转录调控因子Acj6对于调节中枢中间神经元的终末轴突分支和突触发生是必不可少的。在过去的几年中，转录因子相互作用的显着进化保守性已经证明了详细描述像果蝇这样的生物的发育调节机制的价值，这可以更容易地在实验中操纵。从分析Acj6蛋白在果蝇中扮演的基本发育角色中获得的信息可以外推到高等生物，以更好地理解涉及突触连接和某些发育异常的类似过程。

The overall goal of this proposal is to characterize the molecular mechanisms by which synapses between central interneurons are established and modulated. We will work toward that broad goal by (1) further characterizing the function of the Drosophila POU domain transcriptional regulator, Acj6, and its role in establishing correct synaptic connections in the central brain, (2) identifying other components of the pathway(s) regulated by Acj6 during synapse formation and (3) characterizing the role of the amino terminal Acj6 POUIV box in regulating Acj6 function. The specific alms of this proposal are: (1) to identify other components of the pathway(s) regulated by Acj6 through completion of a genetic screen for enhancers and suppressors of the acj6 mutant phenotype, (2) to further characterize the acj6 mutant defects in synaptic connectivity by generating Acj6 neuron-specific expression transposons for use both as cell-specific markers and for misexpression experiments, (3) to characterize the neuron-specific expression of Acj6 isoforms resulting from alternative splicing of the amino terminal POUIV box; and (4) to complete a yeast two-hybrid screen for heterologous proteins interacting with the Acj6 POUIV box. The process of synaptogenesis requires precise initial selection of the correct synaptic partners and subsequent refinement of terminal processes and connections. This process of synaptic selection, refinement, strengthening and/or elimination is thought to be important for learning and memory formation and may lie at the root of a number of neuropathologies. Genetic analysis of synaptic function in the fruit fly, Drosophila melanogaster, has contributed significantly to our knowledge of learning and memory mechanisms. In preliminary studies, we have shown that the Drosophila transcriptional regulator, Acj6, is essential for regulation of terminal axon branching and synaptogenesis in a subset of central interneurons. The significant evolutionary conservation of transcription factor interactions shown over the past several years has demonstrated the value of detailed characterization of developmental regulatory mechanisms in an organism such as Drosophila which can be more readily manipulated experimentally. Information gained from an analysis of the fundamental developmental roles played by the Acj6 protein in Drosophila can be extrapolated to higher organisms to better understand analogous processes involved in synaptic connectivity and certain developmental abnormalities.