Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02454.
National Center for Behavioral Genomics, Department of Biology, Brandeis University, Waltham, MA 02454.
Proc Natl Acad Sci U S A. 2017 Oct 10;114(41):E8780-E8787. doi: 10.1073/pnas.1706608114. Epub 2017 Sep 26.
There are no general methods for reliably assessing the firing properties or even calcium profiles of specific neurons in freely moving flies. To this end, we adapted a GFP-based calcium reporter to luciferase that was expressed in small subsets of circadian neurons. This Tric-LUC reporter allowed a direct comparison of luciferase activity with locomotor activity, which was assayed in the same flies with video recording. The LUC profile from activity-promoting E cells paralleled evening locomotor activity, and the LUC profile from sleep-promoting glutamatergic DN1s (gDN1s) paralleled daytime sleep. Similar profiles were generated by novel reporters recently identified based on transcription factor activation. As E cell and gDN1 activity is necessary and sufficient for normal evening locomotor activity and daytime sleep profiles, respectively, we suggest that their luciferase profiles reflect their neuronal calcium and in some cases firing profiles in wake-behaving flies.
在自由活动的果蝇中，没有可靠的方法来评估特定神经元的放电特性，甚至是钙信号。为此，我们将基于 GFP 的钙报告基因改造为在小部分生物钟神经元中表达的荧光素酶。这种 Tric-LUC 报告基因允许与视频记录中相同的果蝇运动活性直接比较荧光素酶活性。促进活动的 E 细胞的 LUC 图谱与傍晚的运动活性相吻合，而促进睡眠的谷氨酸能 DN1s（gDN1s）的 LUC 图谱则与白天的睡眠相吻合。基于转录因子激活的新报告基因最近也产生了类似的图谱。由于 E 细胞和 gDN1 活性分别是正常傍晚运动活性和白天睡眠模式所必需和充分的，我们推测它们的荧光素酶图谱反映了在清醒活动的果蝇中它们的神经元钙信号，在某些情况下还反映了它们的放电特性。
