Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
J Neurosci. 2010 Jun 9;30(23):8001-11. doi: 10.1523/JNEUROSCI.4636-09.2010.
Insulin signaling plays a prominent role in regulation of dauer formation and longevity in Caenorhabditis elegans. Here, we show that insulin signaling also is required in benzaldehyde-starvation associative plasticity, in which worms pre-exposed to the odor attractant benzaldehyde in the absence of food subsequently demonstrate a conditioned aversion response toward the odorant. Animals with mutations in insulin-related 1 (ins-1), abnormal dauer formation 2 (daf-2), and aging alteration 1 (age-1), which encode the homolog of human insulin, insulin/IGF-1 receptor, and PIP3 kinase, respectively, demonstrated significant deficits in benzaldehyde-starvation associative plasticity. Using a conditional allele, we show that the behavioral roles of DAF-2 signaling in associative plasticity can be dissociated, with DAF-2 signaling playing a more significant role in the memory retrieval than in memory acquisition. We propose DAF-2 signaling acts as a learning-specific starvation signal in the memory acquisition phase of benzaldehyde-starvation associative plasticity but functions to switch benzaldehyde-sensing amphid wing C neurons into an avoidance signaling mode during memory retrieval.
胰岛素信号在秀丽隐杆线虫 dauer 形成和寿命的调节中起着重要作用。在这里，我们表明胰岛素信号在苯甲醛饥饿关联可塑性中也是必需的，在这种可塑性中，蠕虫在没有食物的情况下预先暴露于气味引诱剂苯甲醛，随后对该气味表现出条件厌恶反应。胰岛素相关 1（ins-1）、异常 dauer 形成 2（daf-2）和衰老改变 1（age-1）突变的动物，分别编码人类胰岛素、胰岛素/IGF-1 受体和 PIP3 激酶的同源物，在苯甲醛饥饿关联可塑性方面表现出明显缺陷。使用条件等位基因，我们表明 DAF-2 信号在关联可塑性中的行为作用可以分离，DAF-2 信号在记忆检索中比在记忆获取中起着更重要的作用。我们提出 DAF-2 信号在苯甲醛饥饿关联可塑性的记忆获取阶段作为一种特定于学习的饥饿信号，但在记忆检索过程中，DAF-2 信号将苯甲醛感知触角翼 C 神经元切换到回避信号模式。
