Molecular genetics of neural development and plasticity of the learning and memory centers in Drosophila

蘑菇体是果蝇脑中嗅觉联想学习和基本认知功能的中心。作为一种方法来系统地阐明优先在MB中表达的基因，我们调查了MB转录使用果蝇全基因组微阵列，并选择了102个基因，表现出最一致的减少MB消融大脑中的表达水平。通过原位杂交对幼虫和成虫的表达模式进行体内分析，发现大多数基因的优先MB表达模式是在变态过程中建立的。此外，针对MB神经元发育的RNA干扰导致许多已鉴定基因的轻度至强烈的结构缺陷。我们还开发了一种新的范式幼虫联想学习与一个单一的气味和积极的味觉增味剂，蔗糖。有趣的是，幼虫的记忆产生的食欲调节持续中期，并依赖于健忘症和cAMP反应元件结合蛋白（CREB）。此外，突触输出的幼虫MB神经元的检索所需的，但不是收购和保留的幼虫的记忆，包括CREB依赖的组件。这些结果提供了新的见解，控制MB神经元的分化和重塑的基因库，以及在学习和记忆过程中MB神经元的突触可塑性的功能的神经因子的库。

Mushroom bodies (MBs) are the centers for olfactory associative learning and elementary cognitive functions in the Drosophila brain. As a way to systematically elucidate the genes preferentially expressed in MBs, we surveyed MB transcripts using a Drosophila whole-genome microarray and selected 102 genes that exhibited a most consistent reduction of expression levels in MB ablated brains. In vivo analyses of larval and adult expression patterns by in situ hybridization reveal that the preferential MB expression patterns for most of the genes are established during metamorphosis. Moreover, RNA interference targeted developmentally to the MB neurons resulted in mild to strong structural defects for many of the identified genes. We have also developed a novel paradigm of larval associative learning with a single odor and a positive gustatory reinforcer, sucrose. Intriguingly, larval memory produced by the appetitive conditioning lasts medium-term and depends on both amnesiac and cAMP response element-binding protein (CREB). Moreover, synaptic output of larval MB neurons is required for retrieval but not for acquisition and retention of the larval memory including the CREB-dependent component. These results provide novel insights into the repertoire of the genes that control differentiation and remodeling of the MB neurons as well as the repertoire of neural factors that have functions in the synaptic plasticity of MB neurons during learning and memory.