Monitoring spatio-temporal patterns of gene expression by fluorescent proteins requires longitudinal observation, which is often difficult to implement. Here, we fuse a fluorescent timer (FT) protein with an immediate early gene (IEG) promoter to track live gene expression in single cells. This results in a stimulus- and time-dependent spectral shift from blue to red for subsequent monitoring with fluorescence activated cell sorting (FACS) and live cell imaging. This spectral shift enables imputing the time point of activity post-hoc to dissociate early and late responders from a single snapshot in time. Thus, we provide a tool for tracking stimulus-driven IEG expression and demonstrate proof of concept exploiting promoter::FT fusions, adding new dimensions to experiments that require reconstructing spatio-temporal patterns of gene expression in cells, tissues or living organisms.

中文翻译：

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荧光计时器蛋白对基因表达历史的光谱记录。

通过荧光蛋白监测基因表达的时空模式需要纵向观察，这通常很难实现。在这里，我们将荧光计时器（FT）蛋白与立即早期基因（IEG）启动子融合在一起，以跟踪单细胞中活的基因表达。这会导致从蓝色到红色的刺激和时间相关的光谱偏移，以便随后通过荧光激活细胞分选（FACS）和活细胞成像进行监测。这种频谱偏移可以事后估算活动的时间点以便及时将早期和晚期响应者与单个快照分离。因此，我们提供了一种跟踪刺激驱动的IEG表达的工具，并证明了利用启动子:: FT融合的概念证明，为需要重构细胞，组织或活生物体中基因表达的时空模式的实验增加了新的维度。