Institute of Biochemistry, Goethe-University, Frankfurt, Germany.
PLoS One. 2011 Apr 20;6(4):e18766. doi: 10.1371/journal.pone.0018766.
Channelrhodopsin-2 (ChR2) is widely used for rapid photodepolarization of neurons, yet, as it requires high-intensity blue light for activation, it is not suited for long-term in vivo applications, e.g. for manipulations of behavior, or photoactivation of neurons during development. We used "slow" ChR2 variants with mutations in the C128 residue, that exhibit delayed off-kinetics and increased light sensitivity in Caenorhabditis elegans. Following a 1 s light pulse, we could photodepolarize neurons and muscles for minutes (and with repeated brief stimulation, up to days) with low-intensity light. Photoactivation of ChR2(C128S) in command interneurons elicited long-lasting alterations in locomotion. Finally, we could optically induce profound changes in animal development: Long-term photoactivation of ASJ neurons, which regulate larval growth, bypassed the constitutive entry into the "dauer" larval state in daf-11 mutants. These lack a guanylyl cyclase, which possibly renders ASJ neurons hyperpolarized. Furthermore, photostimulated ASJ neurons could acutely trigger dauer-exit. Thus, slow ChR2s can be employed to long-term photoactivate behavior and to trigger alternative animal development.
通道视紫红质 2（ChR2）广泛用于快速光解神经元，但由于其激活需要高强度蓝光，因此不适合长期体内应用，例如用于行为操纵或在发育过程中光激活神经元。我们使用在 C128 残基发生突变的“慢”ChR2 变体，其在秀丽隐杆线虫中表现出延迟的关动力学和增加的光敏感性。在 1 秒光脉冲后，我们可以用低强度光持续数分钟（通过重复短暂刺激，甚至长达数天）光解神经元和肌肉。命令中间神经元中 ChR2（C128S）的光激活会引起长时间的运动改变。最后，我们可以在动物发育中进行深度诱导：长期光激活调节幼虫生长的 ASJ 神经元，绕过了 daf-11 突变体中组成性进入“ dauer”幼虫状态。这些突变体缺乏一种鸟苷酸环化酶，这可能使 ASJ 神经元超极化。此外，光刺激的 ASJ 神经元可以急性触发 dauer 退出。因此，慢 ChR2 可用于长期光激活行为和触发替代动物发育。
