BACKGROUND In the high-resolution microscopy era, genetic code expansion (GCE)-based bioorthogonal labeling offers an elegant way for direct labeling of proteins in live cells with fluorescent dyes. This labeling approach is currently not broadly used in live-cell applications, partly because it needs to be adjusted to the specific protein under study. RESULTS We present a generic, 14-residue long, N-terminal tag for GCE-based labeling of proteins in live mammalian cells. Using this tag, we generated a library of GCE-based organelle markers, demonstrating the applicability of the tag for labeling a plethora of proteins and organelles. Finally, we show that the HA epitope, used as a backbone in our tag, may be substituted with other epitopes and, in some cases, can be completely removed, reducing the tag length to 5 residues. CONCLUSIONS The GCE-tag presented here offers a powerful, easy-to-implement tool for live-cell labeling of cellular proteins with small and bright probes.

中文翻译：

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一种使用短肽标签对哺乳动物细胞中的蛋白质和细胞器进行生物正交标记的简单方法。

背景技术在高分辨率显微镜时代，基于遗传密码扩展（GCE）的生物正交标记提供了一种用荧光染料直接标记活细胞中蛋白质的简便方法。目前，这种标记方法尚未在活细胞应用中广泛使用，部分原因是需要将其调整为所研究的特定蛋白质。结果我们为活哺乳动物细胞中基于GCE的蛋白质标记提供了一个通用的14个残基长的N末端标签。使用此标签，我们生成了一个基于GCE的细胞器标记物库，证明了该标签可用于标记大量蛋白质和细胞器。最后，我们证明了用作标签中骨架的HA表位可以被其他表位取代，并且在某些情况下可以完全去除，从而将标签长度减少到5个残基。