Article Title: Regulation of Neuronal Excitability through Pumilio- Dependent Control of a Sodium Channel Gene Regulation of Neuronal Excitability through Pumilio- Dependent Control of a Sodium Channel Gene Materials and Methods
Article Title: Regulation of Neuronal Excitability through Pumilio- Dependent Control of a Sodium Channel Gene Regulation of Neuronal Excitability through Pumilio- Dependent Control of a Sodium Channel Gene Materials and Methods
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通讯作者：
C. Mee;Edward C. G. Pym;K. Moffat;R. Baines
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作者：
C. Mee;Edward C. G. Pym;K. Moffat;R. Baines
根据出版商政策，本文件可在线查阅。请向下滚动以查看文档本身。请参阅此项目的存储库记录以及存储库主页上的政策信息以了解更多信息。要查看本文的最终版本，请访问出版商的网站。访问发布的版本可能需要订阅。在胚胎发育和学习过程中发生的突触连接和强度的动态变化有破坏神经回路稳定的趋势。为了克服这一点，神经元已经开发出多种稳态机制来维持生理限定范围内的放电。在这项研究中，我们表明，特定的电压门控Na+通道[麻痹（帕拉）编码]的mRNA的活性依赖性控制有助于调节果蝇运动神经元的膜兴奋性。通过实时逆转录PCR对帕拉mRNA进行定量，结果表明，在突触兴奋升高的CNS中，其水平显著降低，而相反，当突触囊泡释放被阻断时，其水平显著增加。定量的mRNA编码的翻译抑制蛋白pumilio（PUM）揭示了一个相互调节，所看到的段落。Pumilio是足以影响帕拉mRNA。因此，在pum的功能丧失等位基因（pum bemused）中，帕拉mRNA显著升高，而全长pum转基因的表达足以降低帕拉mRNA。在没有PUM的情况下，增加的突触兴奋不能减少帕拉mRNA，表明PUM也是帕拉mRNA活性依赖性调节所必需的。对两个已鉴定的运动神经元（称为aCC和RP 2）中帕拉介导的电压门控Na+电流（I Na）的分析表明，去除pum足以增加两个可分离的I Na组分之一（持续性I Na），而pum转基因的过表达足以抑制两个组分（瞬时和持续性）。我们表明，通过使用海葵毒素（ATX II），在持续性钠离子的改变是足以调节这两个运动神经元的膜兴奋性。中枢神经元必须面对和适应不断变化的突触驱动模式。这些适应对于防止神经元在突触兴奋福尔斯下降时保持沉默或相反地在神经元强烈活动期间变得饱和至关重要。暴露于突触兴奋的变化在早期胚胎发育期间特别极端，此时神经元首次形成突触接触，但也是作为支撑记忆和学习的突触重塑的结果而出现的（对于审查，见虽然这种适应性...
This paper is made available online in accordance with publisher policies. Please scroll down to view the document itself. Please refer to the repository record for this item and our policy information available from the repository home page for further information. To see the final version of this paper please visit the publisher's website. Access to the published version may require a subscription. Dynamic changes in synaptic connectivity and strength, which occur during both embryonic development and learning, have the tendency to destabilize neural circuits. To overcome this, neurons have developed a diversity of homeostatic mechanisms to maintain firing within physiologically defined limits. In this study, we show that activity-dependent control of mRNA for a specific voltage-gated Na ϩ channel [encoded by paralytic (para)] contributes to the regulation of membrane excitability in Drosophila motoneurons. Quantification of para mRNA, by real-time reverse-transcription PCR, shows that levels are significantly decreased in CNSs in which synaptic excitation is elevated, whereas, conversely, they are significantly increased when synaptic vesicle release is blocked. Quantification of mRNA encoding the translational repressor pumilio (pum) reveals a reciprocal regulation to that seen for para. Pumilio is sufficient to influence para mRNA. Thus, para mRNA is significantly elevated in a loss-of-function allele of pum (pum bemused), whereas expression of a full-length pum transgene is sufficient to reduce para mRNA. In the absence of pum, increased synaptic excitation fails to reduce para mRNA, showing that Pum is also necessary for activity-dependent regulation of para mRNA. Analysis of voltage-gated Na ϩ current (I Na) mediated by para in two identified motoneurons (termed aCC and RP2) reveals that removal of pum is sufficient to increase one of two separable I Na components (persistent I Na), whereas overexpression of a pum transgene is sufficient to suppress both components (transient and persistent). We show, through use of anemone toxin (ATX II), that alteration in persistent I Na is sufficient to regulate membrane excitability in these two motoneurons. Introduction Central neurons must face and adapt to changing patterns of synaptic drive. These adaptations are essential to prevent neurons from either falling silent as synaptic excitation falls or, conversely, becoming saturated during periods of intense neuronal activity. Changes in exposure to synaptic excitation are particularly extreme during early embryogenesis when neurons first form syn-aptic contacts, but also arise as a consequence of the synaptic remodeling that underpins memory and learning (for review, see Although such adaptive …