Rational optimization and Imaging in vivo of a genetically encoded optical voltage reporter
Rational optimization and Imaging in vivo of a genetically encoded optical voltage reporter
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DOI：
10.1523/jneurosci.0055-08.2008
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发表时间：
2008-05-21
影响因子：
5.3
通讯作者：
Miesenbock, Gero
中科院分区：
文献类型：
--
作者：
Sjulson, Lucas;Miesenbock, Gero
混合电压传感器（hVOS）结合了膜靶向绿色荧光蛋白和疏水性阴离子双丙胺（DPA），为光学记录基因定义的神经元群的电活动提供了一种有前途的工具。然而，只有在高 DPA 浓度（类似于 3 μM）时才能获得大的荧光信号，从而将膜电容增加到抑制神经活动的水平。在这里，我们开发了传感器的定量模型来指导其优化，并在 2 μM 的较低 DPA 浓度下实现了分数荧光变化的大约三倍。使用这种优化的电压报告器，我们以毫秒时间分辨率对果蝇触角叶中的诱发活动进行光学记录，但未能检测到动作电位，大概是因为即使在降低的 DPA 膜密度下，尖峰的启动和/或传播也会受到添加的电容负载的抑制。我们定量评估了 hVOS 潜在进一步改进的策略，并得出了一般光电压报告器的理论性能限制。
The hybrid voltage sensor (hVOS) combines membrane-targeted green fluorescent protein and the hydrophobic anion dipicrylamine (DPA) to provide a promising tool for optical recording of electrical activity from genetically defined populations of neurons. However, large fluorescence signals are obtained only at high DPA concentrations (similar to 3 mu M) that increase membrane capacitance to a level that suppresses neural activity. Here, we develop a quantitative model of the sensor to guide its optimization and achieved an approximate threefold increase in fractional fluorescence change at a lower DPA concentration of 2 mu M. Using this optimized voltage reporter, we perform optical recordings of evoked activity in the Drosophila antennal lobe with millisecond temporal resolution but fail to detect action potentials, presumably because spike initiation and/or propagation are inhibited by the capacitive load added even at reduced DPA membrane densities. We evaluate strategies for potential further improvement of hVOS quantitatively and derive theoretical performance limits for optical voltage reporters in general.